1 files changed, 49 insertions, 0 deletions
diff --git a/android/fixture_test.go b/android/fixture_test.go
new file mode 100644
index 000000000..7bc033be7
--- /dev/null
+++ b/android/fixture_test.go
@@ -0,0 +1,49 @@
+// Copyright 2021 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package android
+
+import "testing"
+
+// Make sure that FixturePreparer instances are only called once per fixture and in the order in
+// which they were added.
+func TestFixtureDedup(t *testing.T) {
+	list := []string{}
+
+	appendToList := func(s string) FixturePreparer {
+		return FixtureModifyConfig(func(_ Config) {
+			list = append(list, s)
+		})
+	}
+
+	preparer1 := appendToList("preparer1")
+	preparer2 := appendToList("preparer2")
+	preparer3 := appendToList("preparer3")
+	preparer4 := appendToList("preparer4")
+
+	preparer1Then2 := FixturePreparers(preparer1, preparer2)
+
+	preparer2Then1 := FixturePreparers(preparer2, preparer1)
+
+	buildDir := "build"
+	factory := NewFixtureFactory(&buildDir, preparer1, preparer2, preparer1, preparer1Then2)
+
+	extension := factory.Extend(preparer4, preparer2)
+
+	extension.Fixture(t, preparer1, preparer2, preparer2Then1, preparer3)
+
+	h := TestHelper{t}
+	h.AssertDeepEquals("preparers called in wrong order",
+		[]string{"preparer1", "preparer2", "preparer4", "preparer3"}, list)
+}