test: add prompt-score and estimate-cost unit tests (+28 tests)

src/tools/prompt-score.ts

@@ -40,7 +40,7 @@ interface ScoreResult {
   feedback: string[];
 }
 
-function scorePrompt(text: string): ScoreResult {
+export function scorePrompt(text: string): ScoreResult {
   const feedback: string[] = [];
   let specificity: number;
   let scope: number;

tests/tools/prompt-score.test.ts

@@ -0,0 +1,90 @@
+import { describe, it, expect } from "vitest";
+import { scorePrompt } from "../../src/tools/prompt-score.js";
+
+describe("scorePrompt", () => {
+  it("gives high specificity for file paths", () => {
+    const result = scorePrompt("Fix the bug in src/lib/config.ts where the YAML parser crashes on empty files");
+    expect(result.specificity).toBe(25);
+  });
+
+  it("gives high specificity for backtick identifiers", () => {
+    const result = scorePrompt("Rename `loadConfig` to `initConfig`");
+    expect(result.specificity).toBe(25);
+  });
+
+  it("gives medium specificity for generic references", () => {
+    const result = scorePrompt("Fix the component that handles auth");
+    expect(result.specificity).toBe(15);
+  });
+
+  it("gives low specificity for vague prompts", () => {
+    const result = scorePrompt("make it work");
+    expect(result.specificity).toBe(5);
+  });
+
+  it("gives high scope for bounded tasks", () => {
+    const result = scorePrompt("Only update the return type of this single function");
+    expect(result.scope).toBe(25);
+  });
+
+  it("penalizes unbounded scope", () => {
+    const result = scorePrompt("Fix all the bugs");
+    expect(result.scope).toBe(10);
+    expect(result.feedback.some(f => f.includes("broad"))).toBe(true);
+  });
+
+  it("gives high actionability for specific verbs", () => {
+    const result = scorePrompt("Extract the validation logic into a separate function");
+    expect(result.actionability).toBe(25);
+  });
+
+  it("gives medium actionability for vague verbs", () => {
+    const result = scorePrompt("Make the auth flow work better");
+    expect(result.actionability).toBe(15);
+  });
+
+  it("gives high done-condition for verifiable outcomes", () => {
+    const result = scorePrompt("Fix the function so it should return null instead of throwing");
+    expect(result.doneCondition).toBe(25);
+  });
+
+  it("gives good done-condition for questions", () => {
+    const result = scorePrompt("Why is the login page redirecting to a 404?");
+    expect(result.doneCondition).toBe(20);
+  });
+
+  it("grades A+ for excellent prompts", () => {
+    const result = scorePrompt(
+      "Rename `loadConfig` in `src/lib/config.ts` to `initConfig` — only this single function. " +
+      "The tests in `tests/lib/config.test.ts` should still pass after the rename."
+    );
+    expect(result.total).toBeGreaterThanOrEqual(90);
+    expect(result.grade).toBe("A+");
+  });
+
+  it("grades poorly for vague prompts", () => {
+    const result = scorePrompt("fix it");
+    expect(result.total).toBeLessThanOrEqual(45);
+    expect(["D", "F"]).toContain(result.grade);
+  });
+
+  it("provides improvement feedback for weak prompts", () => {
+    const result = scorePrompt("fix it");
+    expect(result.feedback.length).toBeGreaterThan(0);
+    expect(result.feedback.some(f => f.includes("📁"))).toBe(true);
+  });
+
+  it("provides congratulatory feedback for perfect prompts", () => {
+    const result = scorePrompt(
+      "Add only a `validateEmail` function to `src/lib/validators.ts` that should return true for valid emails and nothing else"
+    );
+    // All dimensions maxed → no improvement tips → congratulatory message
+    expect(result.total).toBe(100);
+    expect(result.feedback.some(f => f.includes("🏆"))).toBe(true);
+  });
+
+  it("returns scores that sum to total", () => {
+    const result = scorePrompt("Refactor the auth module to extract token refresh logic");
+    expect(result.specificity + result.scope + result.actionability + result.doneCondition).toBe(result.total);
+  });
+});