feat: Break the issue parsing into a function and test sending various

data to it

src/analyze.ts

@@ -39,8 +39,7 @@ async function runInGitHub(): Promise<void> {
   const retentionDays = parseInt(core.getInput('retention-days') || '7', 10);
   const threadCount = threadCountStr ? parseInt(threadCountStr, 10) : undefined;
   const projectSummary = core.getBooleanInput('project-summary');
-  const issueNumberStr = core.getInput('issue-number')
-  const issueNumber = issueNumberStr ? parseInt(issueNumberStr) : undefined;
+  const issueNumber = parseIssueNumber(core.getInput('issue-number'));
 
   const baseRevision = baseRevisionArg || process.env.GITHUB_BASE_REF;
   if (!baseRevision)
@@ -208,3 +207,17 @@ if (require.main === module) {
   if (process.env.CI) runInGitHub();
   else runLocally();
 }
+
+export function parseIssueNumber(input: unknown): number | undefined {
+  // If the input is a number and it's an integer, return it directly
+  if (typeof input === 'number' && Number.isInteger(input)) {
+    return input;
+  }
+
+  if (typeof input !== 'string') {
+    return undefined;
+  }
+
+  const parsed = parseInt(input);
+  return isNaN(parsed) ? undefined : parsed;
+}

test/analyze.spec.ts

@@ -0,0 +1,40 @@
+import { parseIssueNumber } from '../src/analyze';
+
+describe('parseIssueNumber', () => {
+  it('should return an integer when an integer is provided', () => {
+    expect(parseIssueNumber(123)).toEqual(123);
+  });
+
+  it('should return an integer when a numeric string is provided', () => {
+    expect(parseIssueNumber('123')).toEqual(123);
+  });
+
+  it('should return undefined when a non-numeric string is provided', () => {
+    expect(parseIssueNumber('abc')).toBeUndefined();
+  });
+
+  it('should return undefined when an empty string is provided', () => {
+    expect(parseIssueNumber('')).toBeUndefined();
+  });
+
+  it('should return undefined when a string with spaces is provided', () => {
+    expect(parseIssueNumber('  ')).toBeUndefined();
+  });
+
+  it('should return undefined when a null value is provided', () => {
+    expect(parseIssueNumber(null)).toBeUndefined();
+  });
+
+  it('should return undefined when an undefined value is provided', () => {
+    expect(parseIssueNumber(undefined)).toBeUndefined();
+  });
+
+  it('should return undefined when a boolean value is provided', () => {
+    expect(parseIssueNumber(true)).toBeUndefined();
+    expect(parseIssueNumber(false)).toBeUndefined();
+  });
+
+  it('should return the integer part when a string with a number and letters is provided', () => {
+    expect(parseIssueNumber('123abc')).toEqual(123);
+  });
+});