diff --git a/packages/vc/src/is-credential.test.ts b/packages/vc/src/is-credential.test.ts
new file mode 100644
index 0000000..e40843e
--- /dev/null
+++ b/packages/vc/src/is-credential.test.ts
@@ -0,0 +1,83 @@
+import { describe, expect, it } from "vitest"
+
+import { isCredential } from "./is-credential"
+
+// A minimal valid W3C credential
+const validCredential = {
+  "@context": ["https://www.w3.org/2018/credentials/v1"],
+  type: ["VerifiableCredential"],
+  issuer: { id: "did:web:issuer.example.com" },
+  issuanceDate: "2025-01-01T00:00:00.000Z",
+  credentialSubject: { id: "did:web:subject.example.com" },
+}
+
+describe("isCredential", () => {
+  it("returns true for a valid credential", () => {
+    expect(isCredential(validCredential)).toBe(true)
+  })
+
+  it("accepts issuer as a plain string", () => {
+    expect(
+      isCredential({
+        ...validCredential,
+        issuer: "did:web:issuer.example.com",
+      }),
+    ).toBe(true)
+  })
+
+  it("accepts credentials with optional fields", () => {
+    expect(
+      isCredential({
+        ...validCredential,
+        id: "urn:uuid:123",
+        expirationDate: "2030-01-01T00:00:00.000Z",
+        credentialStatus: {
+          id: "https://status.example.com/1",
+          type: "BitstringStatusListEntry",
+        },
+        proof: { type: "JwtProof2020" },
+      }),
+    ).toBe(true)
+  })
+
+  it("rejects null", () => {
+    expect(isCredential(null)).toBe(false)
+  })
+
+  it("rejects undefined", () => {
+    expect(isCredential(undefined)).toBe(false)
+  })
+
+  it("rejects a plain string", () => {
+    expect(isCredential("not a credential")).toBe(false)
+  })
+
+  it("rejects an empty object", () => {
+    expect(isCredential({})).toBe(false)
+  })
+
+  it("rejects when @context is missing", () => {
+    const { "@context": _, ...noContext } = validCredential
+    expect(isCredential(noContext)).toBe(false)
+  })
+
+  it("rejects when type is missing", () => {
+    const { type: _, ...noType } = validCredential
+    expect(isCredential(noType)).toBe(false)
+  })
+
+  it("rejects when issuer is missing", () => {
+    const { issuer: _, ...noIssuer } = validCredential
+    expect(isCredential(noIssuer)).toBe(false)
+  })
+
+  it("rejects when issuanceDate is missing", () => {
+    const { issuanceDate: _, ...noDate } = validCredential
+    expect(isCredential(noDate)).toBe(false)
+  })
+
+  it("rejects when credentialSubject is missing", () => {
+    const { credentialSubject: _, ...noSubject } = validCredential
+    expect(isCredential(noSubject)).toBe(false)
+  })
+})
diff --git a/packages/vc/src/revocation/is-status-list-credential.test.ts b/packages/vc/src/revocation/is-status-list-credential.test.ts
new file mode 100644
index 0000000..db598d3
--- /dev/null
+++ b/packages/vc/src/revocation/is-status-list-credential.test.ts
@@ -0,0 +1,87 @@
+import { describe, expect, it } from "vitest"
+
+import { isStatusListCredential } from "./is-status-list-credential"
+
+const baseCredential = {
+  "@context": ["https://www.w3.org/2018/credentials/v1"],
+  type: ["VerifiableCredential", "BitstringStatusListCredential"],
+  issuer: { id: "did:web:issuer.example.com" },
+  issuanceDate: "2025-01-01T00:00:00.000Z",
+}
+
+const validStatusListCredential = {
+  ...baseCredential,
+  credentialSubject: {
+    id: "https://status.example.com/list/1",
+    type: "BitstringStatusList",
+    statusPurpose: "revocation",
+    encodedList: "H4sIAAAAAAAA...",
+  },
+}
+
+describe("isStatusListCredential", () => {
+  it("returns true for a valid status list credential", () => {
+    expect(isStatusListCredential(validStatusListCredential)).toBe(true)
+  })
+
+  it("returns false when credentialSubject has wrong type", () => {
+    expect(
+      isStatusListCredential({
+        ...baseCredential,
+        credentialSubject: {
+          id: "https://status.example.com/list/1",
+          type: "SomethingElse",
+          statusPurpose: "revocation",
+          encodedList: "H4sIAAAAAAAA...",
+        },
+      }),
+    ).toBe(false)
+  })
+
+  it("returns false when credentialSubject is missing encodedList", () => {
+    expect(
+      isStatusListCredential({
+        ...baseCredential,
+        credentialSubject: {
+          id: "https://status.example.com/list/1",
+          type: "BitstringStatusList",
+          statusPurpose: "revocation",
+        },
+      }),
+    ).toBe(false)
+  })
+
+  it("returns false when credentialSubject is missing statusPurpose", () => {
+    expect(
+      isStatusListCredential({
+        ...baseCredential,
+        credentialSubject: {
+          id: "https://status.example.com/list/1",
+          type: "BitstringStatusList",
+          encodedList: "H4sIAAAAAAAA...",
+        },
+      }),
+    ).toBe(false)
+  })
+
+  it("returns false for a regular credential without status list subject", () => {
+    expect(
+      isStatusListCredential({
+        ...baseCredential,
+        credentialSubject: { id: "did:web:subject.example.com" },
+      }),
+    ).toBe(false)
+  })
+
+  it("rejects null", () => {
+    expect(isStatusListCredential(null)).toBe(false)
+  })
+
+  it("rejects an empty object", () => {
+    expect(isStatusListCredential({})).toBe(false)
+  })
+
+  it("rejects a plain string", () => {
+    expect(isStatusListCredential("not a credential")).toBe(false)
+  })
+})