fix: make cleaning untracked files resurrected due to git bug testable

lib/gitWorkflow.js

@@ -107,6 +107,18 @@ class GitWorkflow {
     }
   }
 
+  /**
+   * List and delete untracked files
+   */
+  async cleanUntrackedFiles() {
+    const lsFiles = await this.execGit(['ls-files', '--others', '--exclude-standard'])
+    const untrackedFiles = lsFiles
+      .split('\n')
+      .filter(Boolean)
+      .map(file => path.resolve(this.gitDir, file))
+    await Promise.all(untrackedFiles.map(file => unlink(file)))
+  }
+
   /**
    * Create backup stashes, one of everything and one of only staged changes
    * Staged files are left in the index for running tasks
@@ -136,11 +148,7 @@ class GitWorkflow {
 
       // There is a bug in git =< 2.13.0 where `--keep-index` resurrects deleted files.
       // These files should be listed and deleted before proceeding.
-      const untrackedFiles = (await execGit(['ls-files', '--others', '--exclude-standard']))
-        .split('\n')
-        .filter(Boolean)
-        .map(file => path.resolve(this.gitDir, file))
-      await Promise.all(untrackedFiles.map(file => unlink(file)))
+      await this.cleanUntrackedFiles()
 
       // Get a diff of unstaged changes by diffing the saved stash against what's left on disk.
       await this.execGit([

test/file.spec.js

@@ -2,12 +2,12 @@ import { unlink, readFile } from '../lib/file'
 
 describe('unlink', () => {
   it('should throw when second argument is false and file is not found', async () => {
-    await expect(unlink('example', false)).rejects.toThrowError()
+    await expect(unlink('example', false)).rejects.toThrow('ENOENT')
   })
 })
 
 describe('readFile', () => {
   it('should throw when second argument is false and file is not found', async () => {
-    await expect(readFile('example', false)).rejects.toThrowError()
+    await expect(readFile('example', false)).rejects.toThrow('ENOENT')
   })
 })

test/gitWorkflow.spec.js

@@ -91,4 +91,19 @@ describe('gitWorkflow', () => {
       })
     })
   })
+
+  describe('cleanUntrackedFiles', () => {
+    it('should remove untracked files', async () => {
+      const tempFile = path.resolve(cwd, 'tempFile')
+      await fs.writeFile(tempFile, 'Hello')
+
+      const gitWorkflow = new GitWorkflow({
+        gitDir: cwd,
+        gitConfigDir: path.resolve(cwd, './.git')
+      })
+
+      await gitWorkflow.cleanUntrackedFiles()
+      await expect(fs.access(tempFile)).rejects.toThrow('ENOENT')
+    })
+  })
 })