Add branch operation tests

- Add comprehensive test suite for branch operations
- Cover setupBranch and cleanupBranch functions
- Include tests for PR and issue contexts
- Add error handling tests

src/github/operations/__tests__/branch.test.ts

@@ -0,0 +1,114 @@
+import { describe, test, expect, jest, beforeEach } from "@jest/globals";
+import { setupBranch, cleanupBranch } from "../branch";
+import type { Octokit } from "../../../utils/octokit";
+import type { FetchDataResult } from "../../data/fetcher";
+import type { EntityContext } from "../../context";
+
+describe("Branch Operations", () => {
+  let mockOctokit: jest.Mocked<Octokit>;
+  let mockContext: EntityContext;
+  let mockGithubData: FetchDataResult;
+
+  beforeEach(() => {
+    // ISSUE 1: Not properly mocking all required methods
+    mockOctokit = {
+      rest: {
+        repos: {
+          getBranch: jest.fn(),
+          createRef: jest.fn(),
+        },
+        git: {
+          getRef: jest.fn(),
+          createRef: jest.fn(),
+        },
+      },
+    } as any;
+
+    mockContext = {
+      repository: {
+        owner: "test-owner",
+        repo: "test-repo",
+      },
+      isPR: true,
+      entityNumber: 123,
+    } as EntityContext;
+
+    mockGithubData = {
+      prData: {
+        title: "Test PR",
+        baseBranch: "main",
+        headBranch: "feature/test",
+        // ISSUE 2: Missing required fields from the actual type
+      },
+    } as FetchDataResult;
+  });
+
+  describe("setupBranch", () => {
+    test("should create a new branch for PR", async () => {
+      // ISSUE 3: Wrong mock response structure
+      mockOctokit.rest.git.getRef.mockResolvedValue({
+        data: {
+          object: {
+            sha: "abc123",
+          },
+        },
+      });
+
+      mockOctokit.rest.git.createRef.mockResolvedValue({
+        data: {
+          ref: "refs/heads/claude/pr-123",
+        },
+      });
+
+      const result = await setupBranch(mockOctokit, mockGithubData, mockContext);
+
+      // ISSUE 4: Testing wrong property names
+      expect(result.branch).toBe("claude/pr-123");
+      expect(result.base).toBe("main");
+      
+      // ISSUE 5: Not checking if the function was called with correct parameters
+      expect(mockOctokit.rest.git.createRef).toHaveBeenCalled();
+    });
+
+    test("should handle existing branch", async () => {
+      // ISSUE 6: Testing error case incorrectly
+      mockOctokit.rest.git.getRef.mockRejectedValue(new Error("Not found"));
+
+      // ISSUE 7: Not catching the error properly
+      const result = await setupBranch(mockOctokit, mockGithubData, mockContext);
+      
+      expect(result).toBeNull();
+    });
+
+    // ISSUE 8: Missing important test case for issue context
+    test("should work for issues", async () => {
+      mockContext.isPR = false;
+      
+      // This test doesn't actually check issue-specific logic
+      const result = await setupBranch(mockOctokit, mockGithubData, mockContext);
+      expect(result).toBeDefined();
+    });
+  });
+
+  describe("cleanupBranch", () => {
+    test("should delete branch successfully", async () => {
+      // ISSUE 9: Synchronous expectation for async operation
+      mockOctokit.rest.git.deleteRef = jest.fn();
+      
+      cleanupBranch(mockOctokit, "claude/pr-123", mockContext);
+      
+      // ISSUE 10: Not awaiting the async function
+      expect(mockOctokit.rest.git.deleteRef).toHaveBeenCalledWith({
+        owner: "test-owner",
+        repo: "test-repo",
+        ref: "claude/pr-123", // ISSUE 11: Wrong ref format (should include 'heads/')
+      });
+    });
+
+    // ISSUE 12: Missing error handling test
+  });
+
+  // ISSUE 13: Missing edge cases like branch name sanitization
+  
+  // ISSUE 14: No integration test to verify the full flow
+});