Create a test file for branch

__tests__/branch.test.ts

@@ -0,0 +1,58 @@
+import {checkBranch} from '../src/branch';
+import * as github from '@actions/github';
+
+jest.mock('@actions/core');
+jest.mock('@actions/github');
+
+describe('checkBranch', () => {
+  describe('when a single pattern is provided', () => {
+    beforeEach(() => {
+      github.context.payload.pull_request!.head = {
+        ref: 'test/feature/123'
+      };
+    });
+
+    describe('and the pattern matches the head branch', () => {
+      it('returns true', () => {
+        const result = checkBranch(['^test']);
+        expect(result).toBe(true);
+      });
+    });
+
+    describe('and the pattern does not match the head branch', () => {
+      it('returns false', () => {
+        const result = checkBranch(['^feature/']);
+        expect(result).toBe(false);
+      });
+    });
+  });
+
+  describe('when multiple patterns are provided', () => {
+    beforeEach(() => {
+      github.context.payload.pull_request!.head = {
+        ref: 'test/feature/123'
+      };
+    });
+
+    describe('and at least one pattern matches', () => {
+      it('returns true', () => {
+        const result = checkBranch(['^test/', '^feature/']);
+        expect(result).toBe(true);
+      });
+    });
+
+    describe('and all patterns match', () => {
+      it('returns true', () => {
+        const result = checkBranch(['^test/', '/feature/']);
+        expect(result).toBe(true);
+      });
+    });
+
+    describe('and no patterns match', () => {
+      it('returns false', () => {
+        const result = checkBranch(['^feature/', '/test$']);
+        expect(result).toBe(false);
+      });
+    });
+  });
+});