Use a bare git repository for the repo cache.

utils/tests/pub/pub_install_git_test.dart

Index: utils/tests/pub/pub_install_git_test.dart
diff --git a/utils/tests/pub/pub_install_git_test.dart b/utils/tests/pub/pub_install_git_test.dart
index 1c98af149b38b245d4717c5ef9da4306254642bc..56292f76d2b87457c0388a9627ec671c88227d21 100644
--- a/utils/tests/pub/pub_install_git_test.dart
+++ b/utils/tests/pub/pub_install_git_test.dart
@@ -24,8 +24,8 @@ main() {
 
     dir(cachePath, [
       dir('git', [
-        dir('cache', [gitPackageCacheDir('foo')]),
-        gitPackageCacheDir('foo')
+        dir('cache', [gitPackageRepoCacheDir('foo')]),
+        gitPackageRevisionCacheDir('foo')
       ])
     ]).scheduleValidate();
 
@@ -58,11 +58,11 @@ main() {
     dir(cachePath, [
       dir('git', [
         dir('cache', [
-          gitPackageCacheDir('foo'),
-          gitPackageCacheDir('bar')
+          gitPackageRepoCacheDir('foo'),
+          gitPackageRepoCacheDir('bar')
         ]),
-        gitPackageCacheDir('foo'),
-        gitPackageCacheDir('bar')
+        gitPackageRevisionCacheDir('foo'),
+        gitPackageRevisionCacheDir('bar')
       ])
     ]).scheduleValidate();
 
@@ -118,8 +118,8 @@ main() {
 
     dir(cachePath, [
       dir('git', [
-        dir('cache', [gitPackageCacheDir('foo')]),
-        gitPackageCacheDir('foo')
+        dir('cache', [gitPackageRepoCacheDir('foo')]),
+        gitPackageRevisionCacheDir('foo')
       ])
     ]).scheduleValidate();
 
@@ -144,9 +144,9 @@ main() {
     // git/cache directory but create a new git/ directory.
     dir(cachePath, [
       dir('git', [
-        dir('cache', [gitPackageCacheDir('foo', 2)]),
-        gitPackageCacheDir('foo'),
-        gitPackageCacheDir('foo', 2)
+        dir('cache', [gitPackageRepoCacheDir('foo')]),
+        gitPackageRevisionCacheDir('foo'),
+        gitPackageRevisionCacheDir('foo', 2)
       ])
     ]).scheduleValidate();
 
@@ -173,8 +173,8 @@ main() {
 
     dir(cachePath, [
       dir('git', [
-        dir('cache', [gitPackageCacheDir('foo')]),
-        gitPackageCacheDir('foo')
+        dir('cache', [gitPackageRepoCacheDir('foo')]),
+        gitPackageRevisionCacheDir('foo')
       ])
     ]).scheduleValidate();
 
@@ -222,6 +222,33 @@ main() {
     run();
   });
 
+  test('checks out a package at a specific branch from Git', () {
+    ensureGit();
+
+    var repo = git('foo.git', [
+      file('foo.dart', 'main() => "foo 1";')
+    ]);
+    repo.scheduleCreate();
+    repo.scheduleGit(["branch", "old"]);
+
+    git('foo.git', [
+      file('foo.dart', 'main() => "foo 2";')
+    ]).scheduleCommit();
+
+    appDir([{"git": {"url": "../foo.git", "ref": "old"}}]).scheduleCreate();
+
+    schedulePub(args: ['install'],
+        output: const RegExp(@"Dependencies installed!$"));
+
+    dir(packagesPath, [
+      dir('foo', [
+        file('foo.dart', 'main() => "foo 1";')
+      ])
+    ]).scheduleValidate();
+
+    run();
+  });
+
   test('keeps a Git package locked to the version in the lockfile', () {
     ensureGit();
 
@@ -352,8 +379,8 @@ main() {
 
       dir(cachePath, [
         dir('git', [
-          dir('cache', [gitPackageCacheDir('foo')]),
-          gitPackageCacheDir('foo')
+          dir('cache', [gitPackageRepoCacheDir('foo')]),
+          gitPackageRevisionCacheDir('foo')
         ])
       ]).scheduleValidate();