diff --git a/solutions/travis.yml b/.travis.yml
similarity index 100%
rename from solutions/travis.yml
rename to .travis.yml
diff --git a/Pipfile b/Pipfile
new file mode 100644
index 0000000..aede842
--- /dev/null
+++ b/Pipfile
@@ -0,0 +1,13 @@
+[[source]]
+name = "pypi"
+url = "https://pypi.org/simple"
+verify_ssl = true
+
+[dev-packages]
+
+[packages]
+pytest = "*"
+numpy = "*"
+
+[requires]
+python_version = "3.7"
diff --git a/Pipfile.lock b/Pipfile.lock
new file mode 100644
index 0000000..9956e7f
--- /dev/null
+++ b/Pipfile.lock
@@ -0,0 +1,101 @@
+{
+    "_meta": {
+        "hash": {
+            "sha256": "8c364fbe4be6bc611b2c1423f61b9f0a5c5a023d80ba3cc114fe49a5b29a4b8e"
+        },
+        "pipfile-spec": 6,
+        "requires": {
+            "python_version": "3.7"
+        },
+        "sources": [
+            {
+                "name": "pypi",
+                "url": "https://pypi.org/simple",
+                "verify_ssl": true
+            }
+        ]
+    },
+    "default": {
+        "atomicwrites": {
+            "hashes": [
+                "sha256:03472c30eb2c5d1ba9227e4c2ca66ab8287fbfbbda3888aa93dc2e28fc6811b4",
+                "sha256:75a9445bac02d8d058d5e1fe689654ba5a6556a1dfd8ce6ec55a0ed79866cfa6"
+            ],
+            "version": "==1.3.0"
+        },
+        "attrs": {
+            "hashes": [
+                "sha256:69c0dbf2ed392de1cb5ec704444b08a5ef81680a61cb899dc08127123af36a79",
+                "sha256:f0b870f674851ecbfbbbd364d6b5cbdff9dcedbc7f3f5e18a6891057f21fe399"
+            ],
+            "version": "==19.1.0"
+        },
+        "more-itertools": {
+            "hashes": [
+                "sha256:2112d2ca570bb7c3e53ea1a35cd5df42bb0fd10c45f0fb97178679c3c03d64c7",
+                "sha256:c3e4748ba1aad8dba30a4886b0b1a2004f9a863837b8654e7059eebf727afa5a"
+            ],
+            "markers": "python_version > '2.7'",
+            "version": "==7.0.0"
+        },
+        "numpy": {
+            "hashes": [
+                "sha256:0e2eed77804b2a6a88741f8fcac02c5499bba3953ec9c71e8b217fad4912c56c",
+                "sha256:1c666f04553ef70fda54adf097dbae7080645435fc273e2397f26bbf1d127bbb",
+                "sha256:1f46532afa7b2903bfb1b79becca2954c0a04389d19e03dc73f06b039048ac40",
+                "sha256:315fa1b1dfc16ae0f03f8fd1c55f23fd15368710f641d570236f3d78af55e340",
+                "sha256:3d5fcea4f5ed40c3280791d54da3ad2ecf896f4c87c877b113576b8280c59441",
+                "sha256:48241759b99d60aba63b0e590332c600fc4b46ad597c9b0a53f350b871ef0634",
+                "sha256:4b4f2924b36d857cf302aec369caac61e43500c17eeef0d7baacad1084c0ee84",
+                "sha256:54fe3b7ed9e7eb928bbc4318f954d133851865f062fa4bbb02ef8940bc67b5d2",
+                "sha256:5a8f021c70e6206c317974c93eaaf9bc2b56295b6b1cacccf88846e44a1f33fc",
+                "sha256:754a6be26d938e6ca91942804eb209307b73f806a1721176278a6038869a1686",
+                "sha256:771147e654e8b95eea1293174a94f34e2e77d5729ad44aefb62fbf8a79747a15",
+                "sha256:78a6f89da87eeb48014ec652a65c4ffde370c036d780a995edaeb121d3625621",
+                "sha256:7fde5c2a3a682a9e101e61d97696687ebdba47637611378b4127fe7e47fdf2bf",
+                "sha256:80d99399c97f646e873dd8ce87c38cfdbb668956bbc39bc1e6cac4b515bba2a0",
+                "sha256:88a72c1e45a0ae24d1f249a529d9f71fe82e6fa6a3fd61414b829396ec585900",
+                "sha256:a4f4460877a16ac73302a9c077ca545498d9fe64e6a81398d8e1a67e4695e3df",
+                "sha256:a61255a765b3ac73ee4b110b28fccfbf758c985677f526c2b4b39c48cc4b509d",
+                "sha256:ab4896a8c910b9a04c0142871d8800c76c8a2e5ff44763513e1dd9d9631ce897",
+                "sha256:abbd6b1c2ef6199f4b7ca9f818eb6b31f17b73a6110aadc4e4298c3f00fab24e",
+                "sha256:b16d88da290334e33ea992c56492326ea3b06233a00a1855414360b77ca72f26",
+                "sha256:b78a1defedb0e8f6ae1eb55fa6ac74ab42acc4569c3a2eacc2a407ee5d42ebcb",
+                "sha256:cfef82c43b8b29ca436560d51b2251d5117818a8d1fb74a8384a83c096745dad",
+                "sha256:d160e57731fcdec2beda807ebcabf39823c47e9409485b5a3a1db3a8c6ce763e"
+            ],
+            "index": "pypi",
+            "version": "==1.16.3"
+        },
+        "pluggy": {
+            "hashes": [
+                "sha256:19ecf9ce9db2fce065a7a0586e07cfb4ac8614fe96edf628a264b1c70116cf8f",
+                "sha256:84d306a647cc805219916e62aab89caa97a33a1dd8c342e87a37f91073cd4746"
+            ],
+            "version": "==0.9.0"
+        },
+        "py": {
+            "hashes": [
+                "sha256:64f65755aee5b381cea27766a3a147c3f15b9b6b9ac88676de66ba2ae36793fa",
+                "sha256:dc639b046a6e2cff5bbe40194ad65936d6ba360b52b3c3fe1d08a82dd50b5e53"
+            ],
+            "version": "==1.8.0"
+        },
+        "pytest": {
+            "hashes": [
+                "sha256:3773f4c235918987d51daf1db66d51c99fac654c81d6f2f709a046ab446d5e5d",
+                "sha256:b7802283b70ca24d7119b32915efa7c409982f59913c1a6c0640aacf118b95f5"
+            ],
+            "index": "pypi",
+            "version": "==4.4.1"
+        },
+        "six": {
+            "hashes": [
+                "sha256:3350809f0555b11f552448330d0b52d5f24c91a322ea4a15ef22629740f3761c",
+                "sha256:d16a0141ec1a18405cd4ce8b4613101da75da0e9a7aec5bdd4fa804d0e0eba73"
+            ],
+            "version": "==1.12.0"
+        }
+    },
+    "develop": {}
+}
diff --git a/build/lib/pycontest/__init__.py b/build/lib/pycontest/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/build/lib/pycontest/elastic_collisions.py b/build/lib/pycontest/elastic_collisions.py
new file mode 100644
index 0000000..e13140d
--- /dev/null
+++ b/build/lib/pycontest/elastic_collisions.py
@@ -0,0 +1,48 @@
+import numpy as np
+
+def collision_1d(v1_i, v2_i, m1=1, m2=1):
+    """ 1d elastic collisions
+
+    Arguments:
+        v1_1, v2_i: initial values of particles velocities
+        m1, m2: masses
+
+    Returns:
+        final velocities after collisions
+    """
+
+    v1_f = (m1 - m2) / (m1 + m2) * v1_i + 2 * m2 / (m1 + m2) * v2_i
+    v2_f = (m2 - m1) / (m1 + m2) * v2_i + 2 * m1 / (m1 + m2) * v1_i
+    return v1_f, v2_f
+
+
+def collision_2d(v1, v2, r12, m1, m2):
+    """ 2d elastic collisions
+
+    Arguments:
+        v1_1, v2_i: initial values of particles velocities
+        m1, m2: masses
+        r12: vector between particles: r2-r1
+
+    Returns:
+        final velocities after collisions
+    """
+
+    if np.linalg.norm(r12) == 0:
+        raise Exception("two particles are exactly in the same place, "
+                        "consider using smaller time step")
+    n_vect = r12 / np.linalg.norm(r12)
+
+    # scalars
+    v1n = np.dot(v1, n_vect)
+    v2n = np.dot(v2, n_vect)
+    v1s = v1 - v1n * n_vect
+    v2s = v2 - v2n * n_vect
+
+    v1n_f, v2n_f = collision_1d(v1n, v2n, m1, m2)
+    v1n_f *= n_vect
+    v2n_f *= n_vect
+
+    v1_f = v1s + v1n_f
+    v2_f = v2s + v2n_f
+    return v1_f, v2_f
\ No newline at end of file
diff --git a/build/lib/pycontest/movies.py b/build/lib/pycontest/movies.py
new file mode 100644
index 0000000..a3da8a5
--- /dev/null
+++ b/build/lib/pycontest/movies.py
@@ -0,0 +1,126 @@
+import matplotlib
+matplotlib.use("TkAgg")
+import matplotlib.pyplot as plt
+import matplotlib.animation as anm
+import numpy as np
+import math as mt
+import pdb
+
+"""
+Matplotlib Animation Example
+
+author: Jake Vanderplas
+email: vanderplas@astro.washington.edu
+website: http://jakevdp.github.com
+license: BSD
+Please feel free to use and modify this, but keep the above information. Thanks!
+"""
+class Movie_2d:
+
+    def __init__(self, fun, dt, t_max, loc, vel, domain, mass, radius=10):
+        self.dt = dt
+        self.fps = int(mt.floor(1 / dt))
+        self.n_max = int(mt.floor(t_max / dt))
+        self.loc = np.copy(loc)
+        self.vel = np.copy(vel)
+        self.domain = domain
+        self.mass = mass
+        self.radius = radius
+        self.fun = fun
+
+        self.fig = plt.figure()
+        self.fig.subplots_adjust(left=0.1, bottom=0.1, right=.9, top=.9)
+
+        self.ax = self.fig.add_subplot(111, aspect='equal', autoscale_on=False, xlim=(domain[0]), ylim=domain[1])
+        for el in range(loc.shape[0]):
+            self.circ = plt.Circle(self.loc[el, :], self.radius, color='r', fill=False, linewidth=2)
+            self.ax.add_patch(self.circ)
+
+        self.frame = plt.Rectangle([0, 0], domain[0][1] - domain[0][0], domain[1][1] - domain[1][0], fc='none')
+        self.ax.add_patch(self.frame)
+
+    def generate_frame(self, i):
+       # pdb.set_trace()
+        loc, vel = self.fun(self.dt, self.mass, self.radius, self.loc, self.vel, self.domain)
+        #pdb.set_trace()
+        for el in range(loc.shape[0]):
+            self.circ.set_center(loc[el, :])
+        return self.circ, self.frame
+
+    def animate(self, name):
+        animation = anm.FuncAnimation(self.fig, self.generate_frame, frames=self.n_max, interval=10, blit=True)
+
+        fps = self.fps
+        try:
+            animation.save(name + '.mp4', fps=fps, extra_args=['-vcodec', 'libx264'])
+        except ValueError:
+            print("\n mp4 file can not be created, will try to create html")
+            try:
+                animation.save(name + '.html', fps=fps, extra_args=['-vcodec', 'libx264'])
+            except:
+                print("\n html also can not be created")
+
+class Plot_2d:
+
+    def __init__(self, dt, t_max, loc1_0, loc2_0, vel1_0, vel2_0,
+                 domain, radius, m1=1, m2=1, nr=4, nc=5):
+        self.fig = plt.figure()
+        self.nr = nr
+        self.nc = nc
+        self.dt = dt
+        self.t_max = t_max
+        self.loc1_0 = loc1_0
+        self.loc2_0 = loc2_0
+        self.vel1_0 = vel1_0
+        self.vel2_0 = vel2_0
+        self.domain = domain
+        self.radius = radius
+        self.m1 = m1
+        self.m2 = m2
+
+
+    def simulation(self):
+        tt = 0
+        ii = 0
+        loc1, loc2 = self.loc1_0, self.loc2_0
+        vel1, vel2 = self.vel1_0, self.vel2_0
+        while tt <= t_max:
+            [loc1, loc2], [vel1, vel2] = \
+                simulation_step(dt=self.dt, m1=self.m1, m2=self.m2, radius=self.radius,
+                                loc1_0=loc1, loc2_0=loc2, v1_0=vel1, v2_0=vel2,
+                                domain=self.domain)
+            tt += dt
+            if ii % 5 == 0:
+                #pdb.set_trace()
+                self.plotting(ii/5+1, loc1.copy(), loc2.copy(), vel1.copy(), vel2.copy())
+            ii += 1
+        plt.show()
+
+    def plotting(self, ii, loc1, loc2, vel1, vel2):
+        ax = self.fig.add_subplot(self.nr, self.nc, ii, aspect='equal')
+        # ax = plt.gca()
+        # ax.quiver(r1[0], r1[1], r12[0], r12[1], angles='xy', scale_units='xy', scale=1, color="k", width=1.e-3)
+        # ax.quiver(0, 0, r1[0], r1[1], angles='xy', scale_units='xy', scale=1, color="k", width=1.e-3)
+        # ax.quiver(0, 0, r2[0], r2[1], angles='xy', scale_units='xy', scale=1, color="k", width=1.e-3)
+        # ax.quiver(r1[0], r1[1], v1[0], v1[1], angles='xy', scale_units='xy', scale=1, color="g")
+        # ax.quiver(r2[0], r2[1], v2[0], v2[1], angles='xy', scale_units='xy', scale=1, color="g")
+        # ax.quiver(r1[0], r1[1], v1n[0], v1n[1], angles='xy', scale_units='xy', scale=1, color="y")
+        # ax.quiver(r2[0], r2[1], v2n[0], v2n[1], angles='xy', scale_units='xy', scale=1, color="y")
+        # ax.quiver(r1[0], r1[1], v1s[0], v1s[1], angles='xy', scale_units='xy', scale=1, color="y")
+        # ax.quiver(r2[0], r2[1], v2s[0], v2s[1], angles='xy', scale_units='xy', scale=1, color="y")
+        #
+        # ax.quiver(r1[0], r1[1], u1[0], u1[1], angles='xy', scale_units='xy', scale=1, color="b")
+        # ax.quiver(r2[0], r2[1], u2[0], u2[1], angles='xy', scale_units='xy', scale=1, color="b")
+        # ax.quiver(r1[0], r1[1], u1n[0], u1n[1], angles='xy', scale_units='xy', scale=1, color="c")
+        # ax.quiver(r2[0], r2[1], u2n[0], u2n[1], angles='xy', scale_units='xy', scale=1, color="c")
+        # ax.quiver(r1[0], r1[1], u1s[0], u1s[1], angles='xy', scale_units='xy', scale=1, color="c")
+        # ax.quiver(r2[0], r2[1], u2s[0], u2s[1], angles='xy', scale_units='xy', scale=1, color="c")
+
+        # ax.quiver(X, Y, V, U, angles='xy', scale_units='xy', scale=1, color="b")
+        c1 = plt.Circle(loc1, self.radius, color='r', fill=False)
+        c2 = plt.Circle(loc2, self.radius, color='r', fill=False)
+        ax.set_xlim([0, 100])
+        ax.set_ylim([0, 100])
+        # ax.set_aspec("equal")
+        ax.add_patch(c1)
+        ax.add_patch(c2)
diff --git a/build/lib/pycontest/simulation.py b/build/lib/pycontest/simulation.py
new file mode 100644
index 0000000..9ccd19a
--- /dev/null
+++ b/build/lib/pycontest/simulation.py
@@ -0,0 +1,140 @@
+import numpy as np
+import math as mt
+
+from scipy.spatial.distance import pdist, squareform
+
+from pycontest import elastic_collisions as ec
+import pycontest.movies as mv
+from pycontest.transport import transport
+
+
+def simulation_step(dt, mass, radius, loc, vel, domain):
+    """ calculating positions and velocities of particles after one step
+
+    Arguments:
+        dt: time steps
+        mass: masses
+        radius: radius for all balls
+        loc: locations of balls
+        vel: 2d velocities of balls
+        domain: domain for the box
+    Returns:
+         positions and velocities of particles after one step
+    """
+
+
+    # transport
+    loc = transport(loc, vel, dt)
+
+    r12_x = squareform(pdist(loc, lambda r1, r2: r1[0] - r2[0]))
+    r12_y = squareform(pdist(loc, lambda r1, r2: r1[1] - r2[1]))
+    r12 = np.stack((r12_x, r12_y), axis=-1)
+    dist = np.apply_along_axis(np.linalg.norm, 2, r12)
+
+    # finding particles that are colliding
+    ind1, ind2 = np.where(dist < 2 * radius)
+    unique = (ind1 < ind2)
+
+    ind1 = ind1[unique]
+    ind2 = ind2[unique]
+
+    # collisions
+    for id1, id2 in zip(ind1, ind2):
+        vel[id1], vel[id2] = ec.collision_2d(vel[id1], vel[id2], r12[id1, id2], mass[id1], mass[id2])
+
+    # find outside domain points ...
+    out_left   = (loc[:, 0] < domain[0][0] + radius)
+    out_right  = (loc[:, 0] > domain[0][1] - radius)
+    out_top    = (loc[:, 1] < domain[1][0] + radius)
+    out_bottom = (loc[:, 1] > domain[1][1] - radius)
+    
+    # ... change their velocities
+    vel[out_left | out_right,  0] *= -1
+    vel[out_top  | out_bottom, 1] *= -1
+
+    return loc, vel
+
+
+def simulation(t_max, dt, mass, radius, loc_0, vel_0, domain, t0=0):
+    """ calculating positions and velocities of particles after t_max
+
+    Arguments:
+        t_max: length of the simulation
+        dt: time steps
+        mass: masses
+        radius: radius for all balls
+        loc_0: initial locations of balls
+        vel_0: 2d initial velocities of balls
+        t0: initial time (0 as default)
+        domain: domain for the box
+    Returns:
+         positions and velocities of particles at t_max
+    """
+    t = t0
+    loc = np.copy(loc_0)
+    vel = np.copy(vel_0)
+    while(t<t_max):
+        loc, vel = simulation_step(dt, mass, radius, loc, vel, domain)
+        t += dt
+    return loc, vel
+
+
+if __name__ == '__main__':
+    # examples of simulations
+
+    # 2 balls
+    vel = np.array([[12., 12.], [-8, -15.]])
+    loc = np.array([[30., 50.], [30 + (1200) ** 0.5, 50. + 20]])
+    domain = np.array([[0., 100.], [0., 100.]])
+    mass = np.array([1., 2.])
+    dt = 1/30.
+    t_max = 30
+    radius = 10
+
+    movie = mv.Movie_2d(fun=simulation_step, dt=dt, t_max=t_max, loc=loc,
+                        vel=vel, domain=domain, mass=mass, radius=radius)
+    movie.animate("test_2d_2_balls")
+
+
+    # 3 balls
+    vel = np.array([[12., 12.], [-8, -15.], [-3, 4]])
+    loc = np.array([[30., 50.], [30 + (1200) ** 0.5, 50. + 20], [85, 85]])
+    domain = np.array([[0., 100.], [0., 100.]])
+    mass = np.array([1., 2., 1.])
+    dt = 1/30.
+    t_max = 30
+    radius = 10
+
+    movie = mv.Movie_2d(fun=simulation_step, dt=dt, t_max=t_max, loc=loc,
+                        vel=vel, domain=domain, mass=mass, radius=radius)
+    movie.animate("test_2d_3_balls")
+
+
+    # 4 balls
+    vel = np.array([[12., 12.], [-8, -15.], [-3, 4], [10, 0]])
+    loc = np.array([[30., 50.], [30 + (1200) ** 0.5, 50. + 20], [85, 85], [10,10]])
+    domain = np.array([[0., 100.], [0., 100.]])
+    mass = np.array([1., 2., 1., 3])
+    dt = 1 / 30.
+    t_max = 30
+    radius = 10
+
+    movie = mv.Movie_2d(fun=simulation_step, dt=dt, t_max=t_max, loc=loc,
+                        vel=vel, domain=domain, mass=mass, radius=radius)
+    movie.animate("test_2d_4_balls_new")
+
+
+    # many balls
+    vel_many = np.array([[12., 12.], [-8, -15.], [-3, 4], [10, 0], [2., 12.], [-8, -15.],
+                       [3, -4], [-10, 0], [-12., 12.], [8, -15.], [-3, -4], [-10, 0]])
+    loc_many = np.array([[20., 45.], [65, 70.], [85., 90.], [10., 10.], [50., 45.], [15, 70.],
+                    [15., 90.], [45., 10.], [75., 45.], [40, 70.], [45., 90.], [90., 10.]])
+    domain = np.array([[0., 100.], [0., 100.]])
+    mass_many = np.array([1., 2., 1., 3, 1., 2., 1., 3, 1., 2., 1., 3])
+    dt = 1 / 30.
+    t_max = 30
+    radius = 5
+
+    movie = mv.Movie_2d(fun=simulation_step, dt=dt, t_max=t_max, loc=loc_many,
+                        vel=vel_many, domain=domain, mass=mass_many, radius=radius)
+    movie.animate("test_2d_many_balls")
diff --git a/build/lib/pycontest/transport.py b/build/lib/pycontest/transport.py
new file mode 100644
index 0000000..7465a5e
--- /dev/null
+++ b/build/lib/pycontest/transport.py
@@ -0,0 +1,21 @@
+import numpy as np
+
+def transport(loc, vel, dt):
+    """transport equations
+    Args:
+         loc: initial location (can be int/float or array)
+         vel: velocity (can be int/float or array)
+         dt: time step
+
+    Returns:
+        location after one time step
+     """
+
+    # if loc, vel are simple numbers
+    if isinstance(loc, (int, float)) and isinstance(vel, (int, float)):
+        loc = loc + vel * dt
+
+    if isinstance(loc, np.ndarray) and isinstance(vel, np.ndarray):
+        vel = vel.astype(np.float32, copy=False)
+        loc[:] = loc[:] + vel[:] *dt
+    return loc
\ No newline at end of file
diff --git a/build/lib/pycontest/utils.py b/build/lib/pycontest/utils.py
new file mode 100644
index 0000000..ab650c4
--- /dev/null
+++ b/build/lib/pycontest/utils.py
@@ -0,0 +1,30 @@
+import numpy as np
+
+def E_kin(vel, mass):
+    """ calculate the kinematic energy of all particles.
+
+    Arguments:
+        vel: velocities
+        mass: masses
+
+    Returns:
+        Total kinetic energy
+    """
+    vel = np.array(vel)
+    mass = np.array(mass)
+    v_sq = vel**2
+    return 0.5 * np.sum((mass*v_sq.transpose()).transpose())
+
+def momentum(vel, mass):
+    """ calculate the momentum of all particles
+
+    Arguments:
+        vel: velocities
+        mass: masses
+
+    Returns:
+            Total momentum
+    """
+    vel = np.array(vel)
+    mass = np.array(mass)
+    return np.sum((mass*vel.transpose()).transpose(), axis=0)
diff --git a/build/lib/pycontest/version.py b/build/lib/pycontest/version.py
new file mode 100644
index 0000000..0741d66
--- /dev/null
+++ b/build/lib/pycontest/version.py
@@ -0,0 +1,56 @@
+from __future__ import absolute_import, division, print_function
+from os.path import join as pjoin
+
+# Format expected by setup.py and doc/source/conf.py: string of form "X.Y.Z"
+_version_major = 0
+_version_minor = 1
+_version_micro = ''  # use '' for first of series, number for 1 and above
+_version_extra = 'dev'
+# _version_extra = ''  # Uncomment this for full releases
+
+# Construct full version string from these.
+_ver = [_version_major, _version_minor]
+if _version_micro:
+    _ver.append(_version_micro)
+if _version_extra:
+    _ver.append(_version_extra)
+
+__version__ = '.'.join(map(str, _ver))
+
+CLASSIFIERS = ["Development Status :: 3 - Alpha",
+               "Environment :: Console",
+               "Intended Audience :: Science/Research",
+               "License :: OSI Approved :: MIT License",
+               "Operating System :: OS Independent",
+               "Programming Language :: Python",
+               "Topic :: Scientific/Engineering"]
+
+# Description should be a one-liner:
+description = "pycontest: project used during PyCon tutorial"
+# Long description will go up on the pypi page
+long_description = """
+pycontest
+========
+
+License
+=======
+``pycontest`` is licensed under the terms of the MIT license. See the file
+"LICENSE" for information on the history of this software, terms & conditions
+for usage, and a DISCLAIMER OF ALL WARRANTIES.
+"""
+
+NAME = "pycontest"
+MAINTAINER = "Dorota Jatecka & Anna Jaruga"
+MAINTAINER_EMAIL = "djarecka@gmail.com"
+DESCRIPTION = description
+LONG_DESCRIPTION = long_description
+DOWNLOAD_URL = ""
+LICENSE = "MIT"
+AUTHOR = "Dorota Jarecka & Anna Jaruga"
+AUTHOR_EMAIL = "djarecka@gmail.com"
+PLATFORMS = "OS Independent"
+MAJOR = _version_major
+MINOR = _version_minor
+MICRO = _version_micro
+VERSION = __version__
+REQUIRES = ["numpy", "scipy", "matplotlib"]
diff --git a/build/lib/tests/__init__.py b/build/lib/tests/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/build/lib/tests/test_elastic_collisions_1d.py b/build/lib/tests/test_elastic_collisions_1d.py
new file mode 100644
index 0000000..a3c739f
--- /dev/null
+++ b/build/lib/tests/test_elastic_collisions_1d.py
@@ -0,0 +1,13 @@
+import pytest
+
+from pycontest import elastic_collisions as ec
+from pycontest.utils import momentum, E_kin
+
+
+# a simple tests for equal masses (balls should exchange velocities)
+
+# using default values of m1 and m2
+def test_collision_1d_1():
+    v1_f, v2_f = ec.collision_1d(v1_i=1, v2_i=-2)
+
+
diff --git a/build/lib/tests/test_elastic_collisions_2d.py b/build/lib/tests/test_elastic_collisions_2d.py
new file mode 100644
index 0000000..dd9eeac
--- /dev/null
+++ b/build/lib/tests/test_elastic_collisions_2d.py
@@ -0,0 +1,23 @@
+import pytest
+
+from pycontest import elastic_collisions as ec
+from pycontest.utils import momentum, E_kin
+
+
+# 2d are more complicated, depends on the vector r12
+# but we can always check the simplest cases, that are basically 1d cases
+
+# let's start from 2 balls that have only x velocity, and r12 also has only x component
+def test_collision_2d_1():
+    v1_f, v2_f = ec.collision_2d(v1=[1, 0], v2=[-2, 0], r12=[1, 0], m1=1, m2=1)
+    assert (v1_f == [-2, 0]).all()
+    assert (v2_f == [1, 0]).all()
+
+# you cannow do the same for y components
+def test_collision_2d_2():
+    pass
+
+# you can also check the energy and momentum
+
+
+
diff --git a/build/lib/tests/test_hypothesis.py b/build/lib/tests/test_hypothesis.py
new file mode 100644
index 0000000..a529220
--- /dev/null
+++ b/build/lib/tests/test_hypothesis.py
@@ -0,0 +1,14 @@
+import numpy as np
+import pytest
+
+from hypothesis import given, strategies as st
+
+from pycontest import simulation as sim2d
+from pycontest.utils import momentum, E_kin
+
+@pytest.mark.skip(reason="TODO")                                               
+@given(mass1  = st.floats(min_value=.1, max_value=1e3),
+       mass2  = st.floats(min_value=.1, max_value=1e3))
+def test_energy_hypothesis(mass1, mass2):
+
+    pass
diff --git a/build/lib/tests/test_regression.py b/build/lib/tests/test_regression.py
new file mode 100644
index 0000000..e11b8d3
--- /dev/null
+++ b/build/lib/tests/test_regression.py
@@ -0,0 +1,26 @@
+import pycontest
+from pycontest import simulation as sim2d
+import numpy as np                                                             
+import pytest
+import os
+
+@pytest.mark.skip(reason="TODO")
+def test_regression():
+
+    # initial condition and simulation params
+
+    # run simulation
+    loc, vel = sim2d.simulation(...)
+
+    # save reference simulations (only once when the test is created)
+    np.save(os.path.join(os.path.dirname(__file__),"../data/locations_ref.npy"), loc)
+
+    # read in reference values (every time the test is run)
+    loc_ref = np.load(os.path.join(os.path.dirname(__file__), "../data/locations_ref.npy"))
+
+    # from scipy docs:
+    # The tolerance values are positive, typically very small numbers.
+    # The relative difference (rtol * abs(b)) and the absolute difference atol
+    # are added together to compare against the absolute difference 
+    # between a and b.
+    np.testing.assert_allclose(loc, loc_ref, atol=0, rtol=1e-9, err_msg="for locations")
diff --git a/solutions/test_simulation.py b/build/lib/tests/test_simulation.py
similarity index 63%
rename from solutions/test_simulation.py
rename to build/lib/tests/test_simulation.py
index ff18abe..d4d7877 100644
--- a/solutions/test_simulation.py
+++ b/build/lib/tests/test_simulation.py
@@ -5,11 +5,12 @@
 import pytest
 
 
-@pytest.mark.parametrize("dt", [0.5, 0.1, 0.01])
-def test_simulation_1(dt):
+
+def test_simulation_1():
     # initial condition and simulation parameters
     domain = ([-2, 12], [0, 3])
     t_max = 6
+    dt = 0.5
     loc_0 = np.array([[0, 1.5],[10, 1.5]])
     vel_0 = np.array([[1, 0], [-1, 0]])
     radius = 1
@@ -33,18 +34,3 @@ def test_simulation_1(dt):
     assert vel[1][0] == 1
     # Y component should stay the same
     assert (vel[0][1], vel[1][1]) == (vel_0[0][1], vel_0[1][1])
-
-
-def test_simulation_1_fail():
-    # initial condition and simulation parameters
-    domain = ([-2, 12], [0, 3])
-    dt = 1.
-    t_max = 12
-    loc_0 = np.array([[0, 1.5],[10, 1.5]])
-    vel_0 = np.array([[1, 0], [-1, 0]])
-    radius = 1
-    mass = [1, 1]
-    # checking if exception is raised properly
-    with pytest.raises(Exception) as excinfo:
-        loc, vel = sim.simulation(t_max, dt, mass, radius, loc_0, vel_0, domain)
-    assert "two particles are exactly in the same place" in str(excinfo.value)
diff --git a/build/lib/tests/test_simulation_fixture.py b/build/lib/tests/test_simulation_fixture.py
new file mode 100644
index 0000000..38d6048
--- /dev/null
+++ b/build/lib/tests/test_simulation_fixture.py
@@ -0,0 +1,54 @@
+from pycontest import simulation as sim
+from pycontest.utils import E_kin, momentum
+
+import numpy as np
+import pytest
+
+
+@pytest.fixture(scope="module")
+def data(request):
+
+    print("\n create data")
+    # initial condition and simulation parameters
+    domain = ([-2, 12], [0, 3])
+    dt = 0.5
+    t_max = 6
+    loc_0 = np.array([[0, 1.5],[10, 1.5]])
+    vel_0 = np.array([[1, 0], [-1, 0]])
+    radius = 1
+    mass = [1, 1]
+
+    loc, vel = sim.simulation(t_max, dt, mass, radius, loc_0, vel_0, domain)
+
+    my_data = {}
+    my_data["loc_0"] = loc_0
+    my_data["vel_0"] = vel_0
+    my_data["loc"] = loc
+    my_data["vel"] = vel
+    my_data["mass"] = mass
+
+    def data_cleanup():
+        print("\n removing data")
+        my_data.clear()
+
+    request.addfinalizer(data_cleanup)
+    return my_data
+
+
+def test_energy(data):
+
+    print("\n test energy")
+
+    E_ini = E_kin(data["vel_0"], data["mass"])
+    E_end = E_kin(data["vel"], data["mass"])
+
+    assert E_ini == E_end
+
+def test_momentum(data):
+
+    print("\n test momentum")
+
+    p_ini = momentum(data["vel_0"], data["mass"])
+    p_end = momentum(data["vel"], data["mass"])
+
+    assert np.all(p_ini == p_end)
diff --git a/build/lib/tests/test_transport.py b/build/lib/tests/test_transport.py
new file mode 100644
index 0000000..4872524
--- /dev/null
+++ b/build/lib/tests/test_transport.py
@@ -0,0 +1,34 @@
+import numpy as np
+import pytest
+
+from pycontest.transport import transport
+
+
+
+# # first process is transport, and we can easily write a simple test
+ def test_transport_1():
+     loc = 3.
+     vel = 1.
+     dt = .5
+     assert transport(loc, vel, dt) == 3.5
+#
+## but we also want to check if it works for arrays with 2d
+def test_transport_2():
+     loc = np.array([[1, 2], [11, 12]])
+     vel = np. array([[1, 1], [-1, -1]])
+     dt = 1
+     assert (transport(loc, vel, dt) == np.array([[2, 3], [10, 11]])).all()
+
+# # let's try one more, with dt that is float
+ def test_transport_3():
+     loc = np.array([[1, 2], [11, 12]])
+     vel = np. array([[1, 1], [-1, -1]])
+     dt = .5
+     assert (transport(loc, vel, dt) == np.array([[1.5, 2.5], [10.5, 11.5]])).all()
+
+# # and now let's try with lists
+def test_transport_4():
+     loc = [[1, 2], [11, 12]]
+     vel = [[1, 1], [-1, -1]]
+     dt = .5
+     assert (transport(loc, vel, dt) == np.array([[1.5, 2.5], [10.5, 11.5]])).all()
diff --git a/dist/pycontest-0.1.dev0-py3.7.egg b/dist/pycontest-0.1.dev0-py3.7.egg
new file mode 100644
index 0000000..11b609d
Binary files /dev/null and b/dist/pycontest-0.1.dev0-py3.7.egg differ
diff --git a/pycontest.egg-info/PKG-INFO b/pycontest.egg-info/PKG-INFO
new file mode 100644
index 0000000..5c49668
--- /dev/null
+++ b/pycontest.egg-info/PKG-INFO
@@ -0,0 +1,31 @@
+Metadata-Version: 1.2
+Name: pycontest
+Version: 0.1.dev0
+Summary: pycontest: project used during PyCon tutorial
+Home-page: UNKNOWN
+Author: Dorota Jarecka & Anna Jaruga
+Author-email: djarecka@gmail.com
+Maintainer: Dorota Jatecka & Anna Jaruga
+Maintainer-email: djarecka@gmail.com
+License: MIT
+Description: 
+        pycontest
+        ========
+        
+        License
+        =======
+        ``pycontest`` is licensed under the terms of the MIT license. See the file
+        "LICENSE" for information on the history of this software, terms & conditions
+        for usage, and a DISCLAIMER OF ALL WARRANTIES.
+        
+Platform: OS Independent
+Classifier: Development Status :: 3 - Alpha
+Classifier: Environment :: Console
+Classifier: Intended Audience :: Science/Research
+Classifier: License :: OSI Approved :: MIT License
+Classifier: Operating System :: OS Independent
+Classifier: Programming Language :: Python
+Classifier: Topic :: Scientific/Engineering
+Requires: numpy
+Requires: scipy
+Requires: matplotlib
diff --git a/pycontest.egg-info/SOURCES.txt b/pycontest.egg-info/SOURCES.txt
new file mode 100644
index 0000000..825ca05
--- /dev/null
+++ b/pycontest.egg-info/SOURCES.txt
@@ -0,0 +1,22 @@
+README.md
+setup.py
+pycontest/__init__.py
+pycontest/elastic_collisions.py
+pycontest/movies.py
+pycontest/simulation.py
+pycontest/transport.py
+pycontest/utils.py
+pycontest/version.py
+pycontest.egg-info/PKG-INFO
+pycontest.egg-info/SOURCES.txt
+pycontest.egg-info/dependency_links.txt
+pycontest.egg-info/requires.txt
+pycontest.egg-info/top_level.txt
+tests/__init__.py
+tests/test_elastic_collisions_1d.py
+tests/test_elastic_collisions_2d.py
+tests/test_hypothesis.py
+tests/test_regression.py
+tests/test_simulation.py
+tests/test_simulation_fixture.py
+tests/test_transport.py
\ No newline at end of file
diff --git a/pycontest.egg-info/dependency_links.txt b/pycontest.egg-info/dependency_links.txt
new file mode 100644
index 0000000..8b13789
--- /dev/null
+++ b/pycontest.egg-info/dependency_links.txt
@@ -0,0 +1 @@
+
diff --git a/pycontest.egg-info/requires.txt b/pycontest.egg-info/requires.txt
new file mode 100644
index 0000000..f23634b
--- /dev/null
+++ b/pycontest.egg-info/requires.txt
@@ -0,0 +1,3 @@
+numpy
+scipy
+matplotlib
diff --git a/pycontest.egg-info/top_level.txt b/pycontest.egg-info/top_level.txt
new file mode 100644
index 0000000..dc69f55
--- /dev/null
+++ b/pycontest.egg-info/top_level.txt
@@ -0,0 +1,2 @@
+pycontest
+tests
diff --git a/pycontest/transport.py b/pycontest/transport.py
index 7465a5e..404a182 100644
--- a/pycontest/transport.py
+++ b/pycontest/transport.py
@@ -2,20 +2,28 @@
 
 def transport(loc, vel, dt):
     """transport equations
-    Args:
-         loc: initial location (can be int/float or array)
-         vel: velocity (can be int/float or array)
-         dt: time step
-
-    Returns:
-        location after one time step
-     """
+     Args:
+          loc: initial location (can be int/float or array)
+          vel: velocity (can be int/float or array)
+          dt: time step
 
+     Returns:
+         location after one time step
+      """
     # if loc, vel are simple numbers
     if isinstance(loc, (int, float)) and isinstance(vel, (int, float)):
         loc = loc + vel * dt
 
+    # if loc or vel is list, we want to convert to numpy arrays
+    if type(loc) is list:
+        loc = np.array(loc)
+    if type(vel) is list:
+        vel = np.array(vel)
+
+    # for numpy arrays
     if isinstance(loc, np.ndarray) and isinstance(vel, np.ndarray):
+        # be sure that the type is float
+        loc = loc.astype(np.float32, copy=False)
         vel = vel.astype(np.float32, copy=False)
         loc[:] = loc[:] + vel[:] *dt
     return loc
\ No newline at end of file
diff --git a/solutions/test_elastic_collisions_1d.py b/solutions/test_elastic_collisions_1d.py
deleted file mode 100644
index d93589d..0000000
--- a/solutions/test_elastic_collisions_1d.py
+++ /dev/null
@@ -1,45 +0,0 @@
-import pytest
-
-from pycontest import elastic_collisions as ec
-from pycontest.utils import momentum, E_kin
-
-
-# a simple tests for equal masses (balls should exchange velocities)
-
-# using default values of m1 and m2
-def test_collision_1d_1():
-    v1_f, v2_f = ec.collision_1d(v1_i=1, v2_i=-2)
-    assert v1_f == -2
-    assert v2_f == 1
-
-# the same masses, but specifying the values
-def test_collision_1d_2():
-    v1_f, v2_f = ec.collision_1d(v1_i=1, v2_i=-2, m1=2, m2=2)
-    assert v1_f == -2
-    assert v2_f == 1
-
-# we can imagine what happens when one ball is much heavier.
-# The heavy ball won't change the velocity too much
-# we can use pytest.approx
-def test_collision_1d_3():
-    v1_f, v2_f = ec.collision_1d(v1_i=1, v2_i=-2, m1=1, m2=1e6)
-    assert v2_f == pytest.approx(-2, rel=1e-3)
-
-
-
-# it is hard to know the answer when masses are completely independed,
-# but we still can test if we don't break any physical lawa
-# we can tests total kinetic energy and total momentum
-
-def test_collision_1d_en():
-    v1_i, v2_i = 1, -2
-    m1, m2 = 1, 3
-    v1_f, v2_f = ec.collision_1d(v1_i, v2_i, m1, m2)
-    assert E_kin([v1_i, v2_i], [m1, m2]) == E_kin([v1_f, v2_f], [m1, m2])
-
-
-def test_collision_1d_mom():
-    v1_i, v2_i = 1, -2
-    m1, m2 = 1, 3
-    v1_f, v2_f = ec.collision_1d(v1_i, v2_i, m1, m2)
-    assert momentum([v1_i, v2_i], [m1, m2]) == momentum([v1_f, v2_f], [m1, m2])
diff --git a/solutions/test_elastic_collisions_2d.py b/solutions/test_elastic_collisions_2d.py
deleted file mode 100644
index 292cc32..0000000
--- a/solutions/test_elastic_collisions_2d.py
+++ /dev/null
@@ -1,39 +0,0 @@
-import pytest
-
-from pycontest import elastic_collisions as ec
-from pycontest.utils import momentum, E_kin
-
-
-# 2d are more complicated, depends on the vector r12
-# but we can always check the simplest cases, that are basically 1d cases
-
-# let's start from 2 balls that have only x velocity, and r12 also has only x component
-def test_collision_2d_1():
-    v1_f, v2_f = ec.collision_2d(v1=[1, 0], v2=[-2, 0], r12=[1, 0], m1=1, m2=1)
-    assert (v1_f == [-2, 0]).all()
-    assert (v2_f == [1, 0]).all()
-
-# you cannow do the same for y components
-def test_collision_2d_2():
-    v1_f, v2_f = ec.collision_2d(v1=[0, 1], v2=[0, -2], r12=[0, 1], m1=1, m2=1)
-    assert (v1_f == [0, -2]).all()
-    assert (v2_f == [0, 1]).all()
-
-
-# you can also check the energy and momentum
-
-def test_collision_2d_en():
-    v1_i, v2_i = [3, 1], [1, -2]
-    m1, m2 = 1, 2
-    v1_f, v2_f = ec.collision_2d(v1=v1_i, v2=v2_i, r12=[0, 1], m1=m1, m2=m2)
-    assert E_kin([v1_i,v2_i], [m1, m2]) == E_kin([v1_f,v2_f], [m1, m2])
-
-
-def test_collision_2d_mom():
-    v1_i, v2_i = [3, 1], [1, -2]
-    m1, m2 = 1, 2
-    v1_f, v2_f = ec.collision_2d(v1=v1_i, v2=v2_i, r12=[0, 1], m1=m1, m2=m2)
-    assert (momentum([v1_i,v2_i], [m1, m2]) == momentum([v1_f, v2_f], [m1, m2])).all()
-
-
-
diff --git a/solutions/test_hypothesis.py b/solutions/test_hypothesis.py
deleted file mode 100644
index 42495bb..0000000
--- a/solutions/test_hypothesis.py
+++ /dev/null
@@ -1,33 +0,0 @@
-import numpy as np
-import pytest
-
-from hypothesis import given, strategies as st
-
-from pycontest import simulation as sim2d                                      
-from pycontest.utils import momentum, E_kin
-
-# hypothesis simple example
-@given(mass1  = st.floats(min_value=.1, max_value=1e3),
-       mass2  = st.floats(min_value=.1, max_value=1e3))
-def test_energy_hypothesis(mass1, mass2):
-
-    # initial condition and simulation parameters
-    domain = ([0, 20], [0, 20])
-    dt = 0.5
-    t_max = 6
-    loc_0 = np.array([[3, 4],[15, 2]])
-    vel_0 = np.array([[1, 0.5], [-1, -.25]])
-    radius = 1
-
-    # mass chosen by hypothesis
-    mass = [mass1, mass2]
-
-    # run the simulation
-    loc, vel = sim2d.simulation(t_max, dt, mass, radius, loc_0, vel_0, domain)
-
-    E_ini = E_kin(vel_0, mass)
-    E_end = E_kin(vel, mass)
-
-    print("testing for mass = {}. E_end = {}".format(mass, E_end))
-
-    assert E_ini == E_end
diff --git a/solutions/test_regression.py b/solutions/test_regression.py
deleted file mode 100644
index 58a30c9..0000000
--- a/solutions/test_regression.py
+++ /dev/null
@@ -1,37 +0,0 @@
-import pycontest
-from pycontest import simulation as sim2d
-import numpy as np                                                             
-import pytest
-import os
-
-def test_regression():
-
-    # initial condition and simulation params
-    vel_0 = np.array([[12., 12.], [-8, -15.], [-3, 4],     [10, 0],    [2., 12.],  [-8, -15.],
-                      [3,    -4], [-10, 0],   [-12., 12.], [8, -15.],  [-3, -4],   [-10, 0]])
-    loc_0 = np.array([[20., 45.], [65, 70.],  [85., 90.],  [10., 10.], [50., 45.], [15, 70.],
-                      [15., 90.], [45., 10.], [75., 45.],  [40, 70.],  [45., 90.], [90., 10.]])
-    domain = np.array([[0., 100.], [0., 100.]])
-    mass = np.array([1., 2., 1., 3, 1., 2., 1., 3, 1., 2., 1., 3])
-    dt = 1 / 30.
-    t_max = 30
-    radius = 5
-
-    # run simulation
-    loc, vel = sim2d.simulation(t_max, dt, mass, radius, loc_0, vel_0, domain, t0=dt)
-
-    # save reference simulations
-    #np.save(os.path.join(os.path.dirname(__file__),"../data/loc_ref.npy"), loc)
-    #np.save(os.path.join(os.path.dirname(__file__),"../data/vel_ref.npy"), vel)
-
-    # read in reference values
-    loc_ref = np.load(os.path.join(os.path.dirname(__file__), "../data/loc_ref.npy"))
-    vel_ref = np.load(os.path.join(os.path.dirname(__file__), "../data/vel_ref.npy"))
-
-    # from scipy docs:
-    # The tolerance values are positive, typically very small numbers.
-    # The relative difference (rtol * abs(b)) and the absolute difference atol
-    # are added together to compare against the absolute difference 
-    # between a and b.
-    np.testing.assert_allclose(loc, loc_ref, atol=0, rtol=1e-9, err_msg="for locations")
-    np.testing.assert_allclose(vel, vel_ref, atol=0, rtol=1e-7, err_msg="for velocities")
diff --git a/solutions/transport.py b/solutions/transport.py
deleted file mode 100644
index 404a182..0000000
--- a/solutions/transport.py
+++ /dev/null
@@ -1,29 +0,0 @@
-import numpy as np
-
-def transport(loc, vel, dt):
-    """transport equations
-     Args:
-          loc: initial location (can be int/float or array)
-          vel: velocity (can be int/float or array)
-          dt: time step
-
-     Returns:
-         location after one time step
-      """
-    # if loc, vel are simple numbers
-    if isinstance(loc, (int, float)) and isinstance(vel, (int, float)):
-        loc = loc + vel * dt
-
-    # if loc or vel is list, we want to convert to numpy arrays
-    if type(loc) is list:
-        loc = np.array(loc)
-    if type(vel) is list:
-        vel = np.array(vel)
-
-    # for numpy arrays
-    if isinstance(loc, np.ndarray) and isinstance(vel, np.ndarray):
-        # be sure that the type is float
-        loc = loc.astype(np.float32, copy=False)
-        vel = vel.astype(np.float32, copy=False)
-        loc[:] = loc[:] + vel[:] *dt
-    return loc
\ No newline at end of file
diff --git a/tests/test_elastic_collisions_1d.py b/tests/test_elastic_collisions_1d.py
index a3c739f..d93589d 100644
--- a/tests/test_elastic_collisions_1d.py
+++ b/tests/test_elastic_collisions_1d.py
@@ -9,5 +9,37 @@
 # using default values of m1 and m2
 def test_collision_1d_1():
     v1_f, v2_f = ec.collision_1d(v1_i=1, v2_i=-2)
+    assert v1_f == -2
+    assert v2_f == 1
 
+# the same masses, but specifying the values
+def test_collision_1d_2():
+    v1_f, v2_f = ec.collision_1d(v1_i=1, v2_i=-2, m1=2, m2=2)
+    assert v1_f == -2
+    assert v2_f == 1
 
+# we can imagine what happens when one ball is much heavier.
+# The heavy ball won't change the velocity too much
+# we can use pytest.approx
+def test_collision_1d_3():
+    v1_f, v2_f = ec.collision_1d(v1_i=1, v2_i=-2, m1=1, m2=1e6)
+    assert v2_f == pytest.approx(-2, rel=1e-3)
+
+
+
+# it is hard to know the answer when masses are completely independed,
+# but we still can test if we don't break any physical lawa
+# we can tests total kinetic energy and total momentum
+
+def test_collision_1d_en():
+    v1_i, v2_i = 1, -2
+    m1, m2 = 1, 3
+    v1_f, v2_f = ec.collision_1d(v1_i, v2_i, m1, m2)
+    assert E_kin([v1_i, v2_i], [m1, m2]) == E_kin([v1_f, v2_f], [m1, m2])
+
+
+def test_collision_1d_mom():
+    v1_i, v2_i = 1, -2
+    m1, m2 = 1, 3
+    v1_f, v2_f = ec.collision_1d(v1_i, v2_i, m1, m2)
+    assert momentum([v1_i, v2_i], [m1, m2]) == momentum([v1_f, v2_f], [m1, m2])
diff --git a/tests/test_elastic_collisions_2d.py b/tests/test_elastic_collisions_2d.py
index dd9eeac..292cc32 100644
--- a/tests/test_elastic_collisions_2d.py
+++ b/tests/test_elastic_collisions_2d.py
@@ -15,9 +15,25 @@ def test_collision_2d_1():
 
 # you cannow do the same for y components
 def test_collision_2d_2():
-    pass
+    v1_f, v2_f = ec.collision_2d(v1=[0, 1], v2=[0, -2], r12=[0, 1], m1=1, m2=1)
+    assert (v1_f == [0, -2]).all()
+    assert (v2_f == [0, 1]).all()
+
 
 # you can also check the energy and momentum
 
+def test_collision_2d_en():
+    v1_i, v2_i = [3, 1], [1, -2]
+    m1, m2 = 1, 2
+    v1_f, v2_f = ec.collision_2d(v1=v1_i, v2=v2_i, r12=[0, 1], m1=m1, m2=m2)
+    assert E_kin([v1_i,v2_i], [m1, m2]) == E_kin([v1_f,v2_f], [m1, m2])
+
+
+def test_collision_2d_mom():
+    v1_i, v2_i = [3, 1], [1, -2]
+    m1, m2 = 1, 2
+    v1_f, v2_f = ec.collision_2d(v1=v1_i, v2=v2_i, r12=[0, 1], m1=m1, m2=m2)
+    assert (momentum([v1_i,v2_i], [m1, m2]) == momentum([v1_f, v2_f], [m1, m2])).all()
+
 
 
diff --git a/tests/test_hypothesis.py b/tests/test_hypothesis.py
index a529220..42495bb 100644
--- a/tests/test_hypothesis.py
+++ b/tests/test_hypothesis.py
@@ -3,12 +3,31 @@
 
 from hypothesis import given, strategies as st
 
-from pycontest import simulation as sim2d
+from pycontest import simulation as sim2d                                      
 from pycontest.utils import momentum, E_kin
 
-@pytest.mark.skip(reason="TODO")                                               
+# hypothesis simple example
 @given(mass1  = st.floats(min_value=.1, max_value=1e3),
        mass2  = st.floats(min_value=.1, max_value=1e3))
 def test_energy_hypothesis(mass1, mass2):
 
-    pass
+    # initial condition and simulation parameters
+    domain = ([0, 20], [0, 20])
+    dt = 0.5
+    t_max = 6
+    loc_0 = np.array([[3, 4],[15, 2]])
+    vel_0 = np.array([[1, 0.5], [-1, -.25]])
+    radius = 1
+
+    # mass chosen by hypothesis
+    mass = [mass1, mass2]
+
+    # run the simulation
+    loc, vel = sim2d.simulation(t_max, dt, mass, radius, loc_0, vel_0, domain)
+
+    E_ini = E_kin(vel_0, mass)
+    E_end = E_kin(vel, mass)
+
+    print("testing for mass = {}. E_end = {}".format(mass, E_end))
+
+    assert E_ini == E_end
diff --git a/tests/test_regression.py b/tests/test_regression.py
index e11b8d3..58a30c9 100644
--- a/tests/test_regression.py
+++ b/tests/test_regression.py
@@ -4,19 +4,29 @@
 import pytest
 import os
 
-@pytest.mark.skip(reason="TODO")
 def test_regression():
 
     # initial condition and simulation params
+    vel_0 = np.array([[12., 12.], [-8, -15.], [-3, 4],     [10, 0],    [2., 12.],  [-8, -15.],
+                      [3,    -4], [-10, 0],   [-12., 12.], [8, -15.],  [-3, -4],   [-10, 0]])
+    loc_0 = np.array([[20., 45.], [65, 70.],  [85., 90.],  [10., 10.], [50., 45.], [15, 70.],
+                      [15., 90.], [45., 10.], [75., 45.],  [40, 70.],  [45., 90.], [90., 10.]])
+    domain = np.array([[0., 100.], [0., 100.]])
+    mass = np.array([1., 2., 1., 3, 1., 2., 1., 3, 1., 2., 1., 3])
+    dt = 1 / 30.
+    t_max = 30
+    radius = 5
 
     # run simulation
-    loc, vel = sim2d.simulation(...)
+    loc, vel = sim2d.simulation(t_max, dt, mass, radius, loc_0, vel_0, domain, t0=dt)
 
-    # save reference simulations (only once when the test is created)
-    np.save(os.path.join(os.path.dirname(__file__),"../data/locations_ref.npy"), loc)
+    # save reference simulations
+    #np.save(os.path.join(os.path.dirname(__file__),"../data/loc_ref.npy"), loc)
+    #np.save(os.path.join(os.path.dirname(__file__),"../data/vel_ref.npy"), vel)
 
-    # read in reference values (every time the test is run)
-    loc_ref = np.load(os.path.join(os.path.dirname(__file__), "../data/locations_ref.npy"))
+    # read in reference values
+    loc_ref = np.load(os.path.join(os.path.dirname(__file__), "../data/loc_ref.npy"))
+    vel_ref = np.load(os.path.join(os.path.dirname(__file__), "../data/vel_ref.npy"))
 
     # from scipy docs:
     # The tolerance values are positive, typically very small numbers.
@@ -24,3 +34,4 @@ def test_regression():
     # are added together to compare against the absolute difference 
     # between a and b.
     np.testing.assert_allclose(loc, loc_ref, atol=0, rtol=1e-9, err_msg="for locations")
+    np.testing.assert_allclose(vel, vel_ref, atol=0, rtol=1e-7, err_msg="for velocities")
diff --git a/tests/test_simulation.py b/tests/test_simulation.py
index d4d7877..ff18abe 100644
--- a/tests/test_simulation.py
+++ b/tests/test_simulation.py
@@ -5,12 +5,11 @@
 import pytest
 
 
-
-def test_simulation_1():
+@pytest.mark.parametrize("dt", [0.5, 0.1, 0.01])
+def test_simulation_1(dt):
     # initial condition and simulation parameters
     domain = ([-2, 12], [0, 3])
     t_max = 6
-    dt = 0.5
     loc_0 = np.array([[0, 1.5],[10, 1.5]])
     vel_0 = np.array([[1, 0], [-1, 0]])
     radius = 1
@@ -34,3 +33,18 @@ def test_simulation_1():
     assert vel[1][0] == 1
     # Y component should stay the same
     assert (vel[0][1], vel[1][1]) == (vel_0[0][1], vel_0[1][1])
+
+
+def test_simulation_1_fail():
+    # initial condition and simulation parameters
+    domain = ([-2, 12], [0, 3])
+    dt = 1.
+    t_max = 12
+    loc_0 = np.array([[0, 1.5],[10, 1.5]])
+    vel_0 = np.array([[1, 0], [-1, 0]])
+    radius = 1
+    mass = [1, 1]
+    # checking if exception is raised properly
+    with pytest.raises(Exception) as excinfo:
+        loc, vel = sim.simulation(t_max, dt, mass, radius, loc_0, vel_0, domain)
+    assert "two particles are exactly in the same place" in str(excinfo.value)
diff --git a/tests/test_transport.py b/tests/test_transport.py
index de6277a..092428f 100644
--- a/tests/test_transport.py
+++ b/tests/test_transport.py
@@ -4,31 +4,31 @@
 from pycontest.transport import transport
 
 
+
 # # first process is transport, and we can easily write a simple test
-# def test_transport_1():
-#     loc = 3.
-#     vel = 1.
-#     dt = .5
-#     assert transport(loc, vel, dt) == 3.5
-#
-# # but we also want to check if it works for arrays with 2d
-# def test_transport_2():
-#     loc = np.array([[1, 2], [11, 12]])
-#     vel = np. array([[1, 1], [-1, -1]])
-#     dt = 1
-#     assert (transport(loc, vel, dt) == np.array([[2, 3], [10, 11]])).all()
-#
+def test_transport_1():
+    loc = 3.
+    vel = 1.
+    dt = .5
+    assert transport(loc, vel, dt) == 3.5
 #
+## but we also want to check if it works for arrays with 2d
+def test_transport_2():
+    loc = np.array([[1, 2], [11, 12]])
+    vel = np. array([[1, 1], [-1, -1]])
+    dt = 1
+    assert (transport(loc, vel, dt) == np.array([[2, 3], [10, 11]])).all()
+
 # # let's try one more, with dt that is float
-# def test_transport_3():
-#     loc = np.array([[1, 2], [11, 12]])
-#     vel = np. array([[1, 1], [-1, -1]])
-#     dt = .5
-#     assert (transport(loc, vel, dt) == np.array([[1.5, 2.5], [10.5, 11.5]])).all()
-#
+def test_transport_3():
+    loc = np.array([[1, 2], [11, 12]])
+    vel = np. array([[1, 1], [-1, -1]])
+    dt = .5
+    assert (transport(loc, vel, dt) == np.array([[1.5, 2.5], [10.5, 11.5]])).all()
+
 # # and now let's try with lists
-# def test_transport_4():
-#     loc = [[1, 2], [11, 12]]
-#     vel = [[1, 1], [-1, -1]]
-#     dt = .5
-#     assert (transport(loc, vel, dt) == np.array([[1.5, 2.5], [10.5, 11.5]])).all()
+def test_transport_4():
+    loc = [[1, 2], [11, 12]]
+    vel = [[1, 1], [-1, -1]]
+    dt = .5
+    assert (transport(loc, vel, dt) == np.array([[1.5, 2.5], [10.5, 11.5]])).all()