Setup initial mock url request job tests for Cronet

components/cronet/android/test/cronet_tests_jni.cc

Index: components/cronet/android/test/cronet_tests_jni.cc
diff --git a/components/cronet/android/test/cronet_tests_jni.cc b/components/cronet/android/test/cronet_tests_jni.cc
index 88b2b8cf62041c896430ff1f6fec29f811d68fd1..60f510a0d8646e461f70a4615cbcf61472e86764 100644
--- a/components/cronet/android/test/cronet_tests_jni.cc
+++ b/components/cronet/android/test/cronet_tests_jni.cc
@@ -7,14 +7,66 @@
 #include "base/android/base_jni_registrar.h"
 #include "base/android/jni_android.h"
 #include "base/android/jni_registrar.h"
+#include "base/files/file_path.h"
+#include "base/logging.h"
+#include "base/macros.h"
+#include "base/message_loop/message_loop.h"
+#include "base/path_service.h"
 #include "components/cronet/android/cronet_loader.h"
+#include "net/base/net_errors.h"
+#include "net/test/url_request/url_request_failed_job.h"
+#include "net/test/url_request/url_request_mock_http_job.h"
+#include "net/url_request/url_request_filter.h"
 
 namespace {
 
+// A mock URL that will return a 200 response.
+const char* const kMockCronetTestUrl = "http://mock.cronet.success/";
+
+// A mock URL that will result in a failed url request.
+const char* const kMockCronetTestFailedUrl = "http://mock.cronet.failed/";

[mmenke, 2014/09/18 18:31:44]

nit:  const char kMockCronetTestFailedUrl[] is more common (x2), probably
because it makes people think less.

[xunjieli, 2014/09/18 22:45:14]

Done. Thanks for explaining!

+
 const base::android::RegistrationMethod kCronetTestsRegisteredMethods[] = {
   {"BaseAndroid", base::android::RegisterJni},
 };
 
+// static

[mmenke, 2014/09/18 18:31:44]

not static - in an anonymous namespace instead.

[xunjieli, 2014/09/18 22:45:15]

Done. Sorry about the stale doc.

+class CronetMockJobInterceptor : public net::URLRequestInterceptor {

[mmenke, 2014/09/18 18:31:45]

Should include net/url_request/url_request_interceptor.h (Good job on the
headers, by the way - very easy to miss one, but looks like you have them all).

[xunjieli, 2014/09/18 22:45:15]

Done. Thanks!

+ public:
+  CronetMockJobInterceptor() {}
+  virtual ~CronetMockJobInterceptor() {}
+
+  // net::URLRequestJobFactory::ProtocolHandler implementation

[mmenke, 2014/09/18 18:31:44]

nit:  "net::URLRequestInterceptor implementation" (You probably copied a comment
that I forgot to update in a refactor)

[xunjieli, 2014/09/18 22:45:14]

Done. Thanks!

+  virtual net::URLRequestJob* MaybeInterceptRequest(
+      net::URLRequest* request,
+      net::NetworkDelegate* network_delegate) const OVERRIDE {
+    base::FilePath test_files_root;
+    DCHECK(PathService::Get(base::DIR_ANDROID_APP_DATA, &test_files_root));

[mmenke, 2014/09/18 18:31:45]

Don't put code with side effects in DCHECKs (Or checks, for that matter, as they
can regress).

Can do:
bool result = blah;
DCHECK(result);

Or just not check the return value.  I'm fine, either way.  Not sure we have a
preferred style for C++ in Java-driven tests.

[xunjieli, 2014/09/18 22:45:14]

Done. Thanks for explaining!

+    if (request->url() == GURL(kMockCronetTestUrl)) {
+      return new net::URLRequestMockHTTPJob(
+          request,
+          network_delegate,
+          test_files_root.Append("success.html"),
+          base::MessageLoop::current()->message_loop_proxy());
+    }
+    return new net::URLRequestFailedJob(
+        request, network_delegate, net::ERR_FAILED);
+  }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(CronetMockJobInterceptor);
+};
+
+void AddUrlInterceptors() {
+  net::URLRequestFilter* filter = net::URLRequestFilter::GetInstance();
+  DCHECK(filter->AddUrlInterceptor(

[mmenke, 2014/09/18 18:31:44]

Don't put code with side effects in DCHECKs.  Otherwise, when DCHECKs aren't
built into the binary, your code won't work.

Could just make AddUrlInterceptors() return false on failure, and make
JNI_OnLoad return -1 in that case, just like RegisterNativeMethods.

[xunjieli, 2014/09/18 22:45:15]

Done.

+      GURL(kMockCronetTestUrl),
+      scoped_ptr<net::URLRequestInterceptor>(new CronetMockJobInterceptor())));
+  DCHECK(filter->AddUrlInterceptor(
+      GURL(kMockCronetTestFailedUrl),
+      scoped_ptr<net::URLRequestInterceptor>(new CronetMockJobInterceptor())));
+}
+
 }  // namespace
 
 // This is called by the VM when the shared library is first loaded.
@@ -35,6 +87,8 @@ extern "C" jint JNI_OnLoad(JavaVM* vm, void* reserved) {
           arraysize(kCronetTestsRegisteredMethods))) {
     return -1;
   }
+
+  AddUrlInterceptors();
   return cronet_onload;
 }