[Cronet] Enforce Cronet API never modified, only grown

components/cronet/tools/api_static_checks_unittest.py

Index: components/cronet/tools/api_static_checks_unittest.py
diff --git a/components/cronet/tools/api_static_checks_unittest.py b/components/cronet/tools/api_static_checks_unittest.py
index a6907e6dabbb43f1c7d46235a7853e5a3c6a4f95..db4f5c8d901a573a91f849c60a0cf61de5d21cff 100755
--- a/components/cronet/tools/api_static_checks_unittest.py
+++ b/components/cronet/tools/api_static_checks_unittest.py
@@ -14,10 +14,14 @@ import sys
 import tempfile
 import unittest
 
-from tools import api_static_checks
+REPOSITORY_ROOT = os.path.abspath(os.path.join(
+    os.path.dirname(__file__), '..', '..', '..'))
 
+sys.path.append(os.path.join(REPOSITORY_ROOT, 'components'))
+from cronet.tools import api_static_checks
 
-ERROR_PREFIX = (
+
+ERROR_PREFIX_CHECK_API_CALLS = (
 """ERROR: Found the following calls from implementation classes through
        API classes.  These could fail if older API is used that
        does not contain newer methods.  Please call through a
@@ -25,6 +29,28 @@ ERROR_PREFIX = (
 """)
 
 
+ERROR_PREFIX_UPDATE_API = (
+"""ERROR: This API was modified or removed:
+             """)
+
+
+ERROR_SUFFIX_UPDATE_API = (
+"""
+
+       Cronet API methods and classes cannot be modified.
+""")
+
+
+CHECK_API_VERSION_PREFIX = (
+"""DO NOT EDIT THIS FILE, USE update_api.py TO UPDATE IT
+
+""")
+
+
+API_FILENAME = './android/api.txt'
+API_VERSION_FILENAME = './android/api_version.txt'
+
+
 @contextlib.contextmanager
 def capture_output():
   # A contextmanger that collects the stdout and stderr of wrapped code
@@ -44,6 +70,12 @@ class ApiStaticCheckUnitTest(unittest.TestCase):
   def setUp(self):
     self.temp_dir = tempfile.mkdtemp()
     os.chdir(self.temp_dir)
+    os.mkdir('android')
+    with open(API_VERSION_FILENAME, 'w') as api_version_file:
+      api_version_file.write('0')
+    with open(API_FILENAME, 'w') as api_file:
+      api_file.write('}\n')
+    shutil.copytree(os.path.dirname(__file__), 'tools')
 
 
   def tearDown(self):
@@ -55,7 +87,7 @@ class ApiStaticCheckUnitTest(unittest.TestCase):
     # return jar filename.
 
     java_filename = class_name + '.java'
-    class_filename = class_name + '.class'
+    class_filenames = class_name + '*.class'
     jar_filename = class_name + '.jar'
 
     with open(java_filename, 'w') as java_file:
@@ -63,33 +95,141 @@ class ApiStaticCheckUnitTest(unittest.TestCase):
       java_file.write(java)
       java_file.write('}')
     os.system('javac %s' % java_filename)
-    os.system('jar cf %s %s' % (jar_filename, class_filename))
+    os.system('jar cf %s %s' % (jar_filename, class_filenames))
     return jar_filename
 
 
-  def run_test(self, api_java, impl_java):
-    api_jar = self.make_jar(api_java, 'Api')
-    impl_jar = self.make_jar(impl_java, 'Impl')
+  def run_check_api_calls(self, api_java, impl_java):
+    test = self
+    class MockOpts(object):
+      def __init__(self):
+        self.api_jar = test.make_jar(api_java, 'Api')
+        self.impl_jar = [test.make_jar(impl_java, 'Impl')]
+    opts = MockOpts()
     with capture_output() as return_output:
-      return_code = api_static_checks.main(
-          ['--api_jar', api_jar, '--impl_jar', impl_jar])
+      return_code = api_static_checks.check_api_calls(opts)
     return [return_code, return_output[0]]
 
 
-  def test_success(self):
+  def test_check_api_calls_success(self):
     # Test simple classes with functions
-    self.assertEqual(self.run_test('void a(){}', 'void b(){}'), [True, ''])
+    self.assertEqual(self.run_check_api_calls(
+        'void a(){}', 'void b(){}'), [True, ''])
     # Test simple classes with functions calling themselves
-    self.assertEqual(self.run_test(
+    self.assertEqual(self.run_check_api_calls(
         'void a(){} void b(){a();}', 'void c(){} void d(){c();}'), [True, ''])
 
 
-  def test_failure(self):
+  def test_check_api_calls_failure(self):
     # Test static call
-    self.assertEqual(self.run_test(
+    self.assertEqual(self.run_check_api_calls(
         'public static void a(){}', 'void b(){Api.a();}'),
-        [False, ERROR_PREFIX + 'Impl/b -> Api/a:()V\n'])
+        [False, ERROR_PREFIX_CHECK_API_CALLS + 'Impl/b -> Api/a:()V\n'])
     # Test virtual call
-    self.assertEqual(self.run_test(
+    self.assertEqual(self.run_check_api_calls(
         'public void a(){}', 'void b(){new Api().a();}'),
-        [False, ERROR_PREFIX + 'Impl/b -> Api/a:()V\n'])
+        [False, ERROR_PREFIX_CHECK_API_CALLS + 'Impl/b -> Api/a:()V\n'])
+
+
+  def run_check_api_version(self, java):
+    OUT_FILENAME = 'out.txt'
+    return_code = os.system('./tools/update_api.py --api_jar %s > %s' %
+        (self.make_jar(java, 'Api'), OUT_FILENAME))
+    with open(API_FILENAME, 'r') as api_file:
+      api = api_file.read()
+    with open(API_VERSION_FILENAME, 'r') as api_version_file:
+      api_version = api_version_file.read()
+    with open(OUT_FILENAME, 'r') as out_file:
+      output = out_file.read()
+    return [return_code == 0, output, api, api_version]
+
+
+  def test_update_api_success(self):
+    # Test simple new API
+    self.assertEqual(self.run_check_api_version(
+        'public void a(){}'),
+        [True, '', CHECK_API_VERSION_PREFIX + """public class Api {
+  public Api();
+  public void a();
+}
+""", '1'])
+    # Test version number not increased when API not changed
+    self.assertEqual(self.run_check_api_version(
+        'public void a(){}'),
+        [True, '', CHECK_API_VERSION_PREFIX + """public class Api {
+  public Api();
+  public void a();
+}
+""", '1'])
+    # Test acceptable API method addition
+    self.assertEqual(self.run_check_api_version(
+        'public void a(){} public void b(){}'),
+        [True, '', CHECK_API_VERSION_PREFIX + """public class Api {
+  public Api();
+  public void a();
+  public void b();
+}
+""", '2'])
+    # Test version number not increased when API not changed
+    self.assertEqual(self.run_check_api_version(
+        'public void a(){} public void b(){}'),
+        [True, '', CHECK_API_VERSION_PREFIX + """public class Api {
+  public Api();
+  public void a();
+  public void b();
+}
+""", '2'])
+    # Test acceptable API class addition
+    self.assertEqual(self.run_check_api_version(
+        'public void a(){} public void b(){} public class C {}'),
+        [True, '', CHECK_API_VERSION_PREFIX + """public class Api$C {
+  public Api$C(Api);
+}
+public class Api {
+  public Api();
+  public void a();
+  public void b();
+}
+""", '3'])
+    # Test version number not increased when API not changed
+    self.assertEqual(self.run_check_api_version(
+        'public void a(){} public void b(){} public class C {}'),
+        [True, '', CHECK_API_VERSION_PREFIX + """public class Api$C {
+  public Api$C(Api);
+}
+public class Api {
+  public Api();
+  public void a();
+  public void b();
+}
+""", '3'])
+
+
+  def test_update_api_failure(self):
+    # Create a simple new API
+    self.assertEqual(self.run_check_api_version(
+        'public void a(){}'),
+        [True, '', CHECK_API_VERSION_PREFIX + """public class Api {
+  public Api();
+  public void a();
+}
+""", '1'])
+    # Test removing API method not allowed
+    self.assertEqual(self.run_check_api_version(''),
+        [False, ERROR_PREFIX_UPDATE_API + 'public void a();'
+            + ERROR_SUFFIX_UPDATE_API,
+            CHECK_API_VERSION_PREFIX + """public class Api {
+  public Api();
+  public void a();
+}
+""", '1'])
+    # Test modifying API method not allowed
+    self.assertEqual(self.run_check_api_version(
+        'public void a(int x){}'),
+        [False, ERROR_PREFIX_UPDATE_API + 'public void a();'
+            + ERROR_SUFFIX_UPDATE_API,
+            CHECK_API_VERSION_PREFIX + """public class Api {
+  public Api();
+  public void a();
+}
+""", '1'])