[Cronet] Enforce Cronet API never modified, only grown

components/cronet/tools/api_static_checks_unittest.py

 #!/usr/bin/python
 # Copyright 2016 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """api_static_checks_unittest.py - Unittests for api_static_checks.py"""
 
 
 import contextlib
 from cStringIO import StringIO
 import os
 import shutil
 import sys
 import tempfile
 import unittest
 
 from 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
        wrapper class from VersionSafeCallbacks.
 """)
 
 
+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
 
   oldout,olderr = sys.stdout, sys.stderr
   try:
     out=[StringIO(), StringIO()]
     sys.stdout,sys.stderr = out
     yield out
   finally:
     sys.stdout,sys.stderr = oldout, olderr
     out[0] = out[0].getvalue()
     out[1] = out[1].getvalue()
 
 
 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):
     shutil.rmtree(self.temp_dir)
 
 
   def make_jar(self, java, class_name):
     # Compile |java| wrapped in a class named |class_name| to a jar file and
     # 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:
       java_file.write('public class %s {' % class_name)
       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'])