Add a tool for merging annotation.zip files

We now produce annotation.zip files individually for each module, but
for the public SDK it's easier to distribute a single zip file with
merged contents. Add a tool for merging these (simple) files.

Bug: 187397779
Test: unittest in cl
Test: diff tests in follow-on CL merging all module annotations.zip
Change-Id: Ic5bb94425dccafab43340805f73fafacab53cb28
diff --git a/api/merge_annotation_zips_test.py b/api/merge_annotation_zips_test.py
new file mode 100644
index 0000000..26795c47
--- /dev/null
+++ b/api/merge_annotation_zips_test.py
@@ -0,0 +1,124 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2021 The Android Open Source Project
+#
+# 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.
+
+import io
+from pathlib import Path
+import tempfile
+import unittest
+import zipfile
+
+import merge_annotation_zips
+
+
+zip_a = {
+  'android/provider/annotations.xml':
+  """<?xml version="1.0" encoding="UTF-8"?>
+<root>
+  <item name="android.provider.BlockedNumberContract boolean isBlocked(android.content.Context, java.lang.String)">
+    <annotation name="androidx.annotation.WorkerThread"/>
+  </item>
+  <item name="android.provider.SimPhonebookContract.SimRecords android.net.Uri getItemUri(int, int, int) 2">
+    <annotation name="androidx.annotation.IntRange">
+      <val name="from" val="1" />
+    </annotation>
+  </item>
+</root>""",
+  'android/os/annotations.xml':
+  """<?xml version="1.0" encoding="UTF-8"?>
+<root>
+  <item name="android.app.ActionBar void setCustomView(int) 0">
+    <annotation name="androidx.annotation.LayoutRes"/>
+  </item>
+</root>
+"""
+}
+
+zip_b = {
+  'android/provider/annotations.xml':
+  """<?xml version="1.0" encoding="UTF-8"?>
+<root>
+  <item name="android.provider.MediaStore QUERY_ARG_MATCH_FAVORITE">
+    <annotation name="androidx.annotation.IntDef">
+      <val name="value" val="{android.provider.MediaStore.MATCH_DEFAULT, android.provider.MediaStore.MATCH_INCLUDE, android.provider.MediaStore.MATCH_EXCLUDE, android.provider.MediaStore.MATCH_ONLY}" />
+      <val name="flag" val="true" />
+    </annotation>
+  </item>
+  <item name="android.provider.MediaStore QUERY_ARG_MATCH_PENDING">
+    <annotation name="androidx.annotation.IntDef">
+      <val name="value" val="{android.provider.MediaStore.MATCH_DEFAULT, android.provider.MediaStore.MATCH_INCLUDE, android.provider.MediaStore.MATCH_EXCLUDE, android.provider.MediaStore.MATCH_ONLY}" />
+      <val name="flag" val="true" />
+    </annotation>
+  </item>
+</root>"""
+}
+
+zip_c = {
+  'android/app/annotations.xml':
+  """<?xml version="1.0" encoding="UTF-8"?>
+<root>
+  <item name="android.app.ActionBar void setCustomView(int) 0">
+    <annotation name="androidx.annotation.LayoutRes"/>
+  </item>
+</root>"""
+}
+
+merged_provider = """<?xml version='1.0' encoding='UTF-8'?>
+<root>
+  <item name="android.provider.BlockedNumberContract boolean isBlocked(android.content.Context, java.lang.String)">
+    <annotation name="androidx.annotation.WorkerThread" />
+  </item>
+  <item name="android.provider.MediaStore QUERY_ARG_MATCH_FAVORITE">
+    <annotation name="androidx.annotation.IntDef">
+      <val name="value" val="{android.provider.MediaStore.MATCH_DEFAULT, android.provider.MediaStore.MATCH_INCLUDE, android.provider.MediaStore.MATCH_EXCLUDE, android.provider.MediaStore.MATCH_ONLY}" />
+      <val name="flag" val="true" />
+    </annotation>
+  </item>
+  <item name="android.provider.MediaStore QUERY_ARG_MATCH_PENDING">
+    <annotation name="androidx.annotation.IntDef">
+      <val name="value" val="{android.provider.MediaStore.MATCH_DEFAULT, android.provider.MediaStore.MATCH_INCLUDE, android.provider.MediaStore.MATCH_EXCLUDE, android.provider.MediaStore.MATCH_ONLY}" />
+      <val name="flag" val="true" />
+    </annotation>
+  </item>
+<item name="android.provider.SimPhonebookContract.SimRecords android.net.Uri getItemUri(int, int, int) 2">
+    <annotation name="androidx.annotation.IntRange">
+      <val name="from" val="1" />
+    </annotation>
+  </item>
+</root>"""
+
+
+
+class MergeAnnotationZipsTest(unittest.TestCase):
+
+  def test_merge_zips(self):
+    with tempfile.TemporaryDirectory() as out_dir:
+      for zip_content in [zip_a, zip_b, zip_c]:
+        f = io.BytesIO()
+        with zipfile.ZipFile(f, "w") as zip_file:
+          for filename, content in zip_content.items():
+            zip_file.writestr(filename, content)
+          merge_annotation_zips.merge_zip_file(out_dir, zip_file)
+
+      # Unchanged
+      self.assertEqual(zip_a['android/os/annotations.xml'], Path(out_dir, 'android/os/annotations.xml').read_text())
+      self.assertEqual(zip_c['android/app/annotations.xml'], Path(out_dir, 'android/app/annotations.xml').read_text())
+
+      # Merged
+      self.assertEqual(merged_provider, Path(out_dir, 'android/provider/annotations.xml').read_text())
+
+
+if __name__ == "__main__":
+  unittest.main(verbosity=2)