test : added unit tests for repo-health scoring functions

src/lib/repo-health.ts

@@ -8,13 +8,13 @@ function clamp(n: number, min: number, max: number): number {
   return Math.min(max, Math.max(min, n));
 }
 
-function scoreCommitFrequency(commits30d: number): number {
+export function scoreCommitFrequency(commits30d: number): number {
   // 10+ commits => full 25 points; linear below
   const normalized = clamp(commits30d / 10, 0, 1);
   return normalized * 25;
 }
 
-function scorePrMergeRate(rate: number): number {
+export function scorePrMergeRate(rate: number): number {
   // rate is already 0-1
   return clamp(rate, 0, 1) * 25;
 }
@@ -27,23 +27,23 @@ export function scoreAvgPrOpenTimeHours(avgHours: number): number {
   return clamp(normalized, 0, 1) * 20;
 }
 
-function scoreOpenIssuesCount(openIssues: number): number {
+export function scoreOpenIssuesCount(openIssues: number): number {
   // 0 issues => full 15; 20+ => 0; linear in between
   if (openIssues <= 0) return 15;
   if (openIssues >= 20) return 0;
   const normalized = 1 - openIssues / 20;
   return clamp(normalized, 0, 1) * 15;
 }
 
-function scoreDaysSinceLastCommit(days: number): number {
+export function scoreDaysSinceLastCommit(days: number): number {
   // <7 days => full 15; 7-30 => scale down linearly; >30 => 0
   if (days <= 7) return 15;
   if (days >= 30) return 0;
   const normalized = 1 - (days - 7) / (30 - 7);
   return clamp(normalized, 0, 1) * 15;
 }
 
-function gradeForScore(score: number): RepoHealthScore["grade"] {
+export function gradeForScore(score: number): RepoHealthScore["grade"] {
   if (score >= 70) return "green";
   if (score >= 40) return "yellow";
   return "red";

test/repo-health-scoring.test.ts

@@ -1,5 +1,5 @@
 import { describe, it, expect } from 'vitest';
-import { scoreAvgPrOpenTimeHours, computeHealthScore } from '../src/lib/repo-health';
+import { scoreAvgPrOpenTimeHours, computeHealthScore, scoreCommitFrequency, scorePrMergeRate, scoreOpenIssuesCount, scoreDaysSinceLastCommit } from '../src/lib/repo-health';
 import type { RepoHealthSignals } from '../src/types/repo-health';
 
 describe('gradeForScore', () => {
@@ -98,3 +98,88 @@ describe('scoreAvgPrOpenTimeHours', () => {
     expect(scoreAvgPrOpenTimeHours(-10)).toBe(20);
   });
 });
+
+describe('scoreCommitFrequency', () => {
+  it('returns 0 for zero commits', () => {
+    expect(scoreCommitFrequency(0)).toBe(0);
+  });
+
+  it('returns 25 for 10+ commits', () => {
+    expect(scoreCommitFrequency(10)).toBe(25);
+    expect(scoreCommitFrequency(15)).toBe(25);
+  });
+
+  it('scales linearly between 0 and 10 commits', () => {
+    expect(scoreCommitFrequency(5)).toBe(12.5);
+    expect(scoreCommitFrequency(2.5)).toBe(6.25);
+  });
+
+  it('handles negative values', () => {
+    expect(scoreCommitFrequency(-5)).toBe(0);
+  });
+
+  it('handles non-finite values', () => {
+    expect(scoreCommitFrequency(NaN)).toBe(0);
+  });
+});
+
+describe('scorePrMergeRate', () => {
+  it('returns 0 for 0% merge rate', () => {
+    expect(scorePrMergeRate(0)).toBe(0);
+  });
+
+  it('returns 25 for 100% merge rate', () => {
+    expect(scorePrMergeRate(1)).toBe(25);
+  });
+
+  it('scales linearly between 0 and 1', () => {
+    expect(scorePrMergeRate(0.5)).toBe(12.5);
+  });
+
+  it('handles values outside 0-1 range', () => {
+    expect(scorePrMergeRate(-0.5)).toBe(0);
+    expect(scorePrMergeRate(1.5)).toBe(25);
+  });
+});
+
+describe('scoreOpenIssuesCount', () => {
+  it('returns 15 for 0 issues', () => {
+    expect(scoreOpenIssuesCount(0)).toBe(15);
+  });
+
+  it('returns 0 for 20+ issues', () => {
+    expect(scoreOpenIssuesCount(20)).toBe(0);
+    expect(scoreOpenIssuesCount(50)).toBe(0);
+  });
+
+  it('scales linearly between 0 and 20', () => {
+    expect(scoreOpenIssuesCount(10)).toBe(7.5);
+  });
+
+  it('handles negative values', () => {
+    expect(scoreOpenIssuesCount(-5)).toBe(15);
+  });
+});
+
+describe('scoreDaysSinceLastCommit', () => {
+  it('returns 15 for 0 days', () => {
+    expect(scoreDaysSinceLastCommit(0)).toBe(15);
+  });
+
+  it('returns 15 for 7 days', () => {
+    expect(scoreDaysSinceLastCommit(7)).toBe(15);
+  });
+
+  it('returns 0 for 30+ days', () => {
+    expect(scoreDaysSinceLastCommit(30)).toBe(0);
+    expect(scoreDaysSinceLastCommit(100)).toBe(0);
+  });
+
+  it('scales linearly between 7 and 30 days', () => {
+    expect(scoreDaysSinceLastCommit(18.5)).toBe(7.5);
+  });
+
+  it('handles negative values', () => {
+    expect(scoreDaysSinceLastCommit(-5)).toBe(15);
+  });
+});