add tests for building file changes

src/create-or-update-branch.ts

@@ -48,6 +48,38 @@ export async function tryFetch(
   }
 }
 
+export async function buildFileChanges(
+  git: GitCommandManager,
+  base: string,
+  branch: string
+): Promise<FileChanges> {
+  const fileChanges: FileChanges = {
+    additions: [],
+    deletions: []
+  }
+  const changedFiles = await git.getChangedFiles([
+    '--diff-filter=AM',
+    `${base}..${branch}`
+  ])
+  const deletedFiles = await git.getChangedFiles([
+    '--diff-filter=D',
+    `${base}..${branch}`
+  ])
+  const repoPath = git.getWorkingDirectory()
+  for (const file of changedFiles) {
+    fileChanges.additions!.push({
+      path: file,
+      contents: utils.readFileBase64([repoPath, file])
+    })
+  }
+  for (const file of deletedFiles) {
+    fileChanges.deletions!.push({
+      path: file
+    })
+  }
+  return fileChanges
+}
+
 // Return the number of commits that branch2 is ahead of branch1
 async function commitsAhead(
   git: GitCommandManager,
@@ -111,20 +143,22 @@ function splitLines(multilineString: string): string[] {
     .filter(x => x !== '')
 }
 
+interface FileChanges {
+  additions: {
+    path: string
+    contents: string
+  }[]
+  deletions: {
+    path: string
+  }[]
+}
+
 interface CreateOrUpdateBranchResult {
   action: string
   base: string
   hasDiffWithBase: boolean
   headSha: string
-  fileChanges?: {
-    additions: {
-      path: string
-      contents: string
-    }[]
-    deletions: {
-      path: string
-    }[]
-  }
+  fileChanges?: FileChanges
 }
 
 export async function createOrUpdateBranch(
@@ -300,39 +334,7 @@ export async function createOrUpdateBranch(
   }
 
   if (result.hasDiffWithBase) {
-    // Build file changes
-    result.fileChanges = {
-      additions: [],
-      deletions: []
-    }
-
-    const changedFiles = await git.getChangedFiles([
-      '--diff-filter=M',
-      `${base}..${branch}`
-    ])
-    const deletedFiles = await git.getChangedFiles([
-      '--diff-filter=D',
-      `${base}..${branch}`
-    ])
-
-    core.debug(`Changed files: '${JSON.stringify(changedFiles)}'`)
-    core.debug(`Deleted files: '${JSON.stringify(deletedFiles)}'`)
-
-    const repoPath = git.getWorkingDirectory()
-    for (const file of changedFiles) {
-      core.debug(`Reading contents of file: '${file}'`)
-      result.fileChanges.additions!.push({
-        path: file,
-        contents: utils.readFileBase64([repoPath, file])
-      })
-    }
-
-    for (const file of deletedFiles) {
-      core.debug(`Marking file as deleted: '${file}'`)
-      result.fileChanges.deletions!.push({
-        path: file
-      })
-    }
+    result.fileChanges = await buildFileChanges(git, base, branch)
   }
 
   // Get the pull request branch SHA