Instrument serial API code to make testing easier.

chrome/browser/extensions/api/serial/serial_apitest.cc

Index: chrome/browser/extensions/api/serial/serial_apitest.cc
diff --git a/chrome/browser/extensions/api/serial/serial_apitest.cc b/chrome/browser/extensions/api/serial/serial_apitest.cc
index cf31f19db78da1e698e4a8ae0bc7aa63b8df77ac..e72853e6d0361a225095e4c3a3c53a93f566aa21 100644
--- a/chrome/browser/extensions/api/serial/serial_apitest.cc
+++ b/chrome/browser/extensions/api/serial/serial_apitest.cc
@@ -2,9 +2,14 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include <string>
+
 #include "base/memory/scoped_ptr.h"
+#include "chrome/browser/extensions/api/api_resource_event_notifier.h"
 #include "chrome/browser/extensions/api/serial/serial_api.h"
+#include "chrome/browser/extensions/api/serial/serial_connection.h"
 #include "chrome/browser/extensions/extension_apitest.h"
+#include "chrome/browser/extensions/extension_function.h"
 #include "chrome/browser/extensions/extension_function_test_utils.h"
 #include "chrome/browser/extensions/extension_test_message_listener.h"
 #include "chrome/browser/ui/browser.h"
@@ -21,39 +26,138 @@ class SerialApiTest : public PlatformAppApiTest {
 
 }  // namespace
 
+namespace extensions {
+
+class FakeSerialGetPortsFunction : public AsyncExtensionFunction {
+ public:
+  virtual bool RunImpl() {
+    ListValue* ports = new ListValue();
+    ports->Append(Value::CreateStringValue("/dev/fakeserial"));
+    ports->Append(Value::CreateStringValue("\\\\COM800\\"));
+    result_.reset(ports);
+    SendResponse(true);
+    return true;
+  }
+};
+
+class FakeEchoSerialConnection : public SerialConnection {
+ public:
+  explicit FakeEchoSerialConnection(
+      const std::string& port,
+      int bitrate,
+      APIResourceEventNotifier* event_notifier)
+      : SerialConnection(port, bitrate, event_notifier),
+        opened_(true) {
+    Flush();
+    opened_ = false;
+  }
+
+  virtual bool Open() {
+    DCHECK(!opened_);
+    opened_ = true;
+    return true;
+  }
+
+  virtual void Close() {
+    DCHECK(opened_);
+  }
+
+  virtual void Flush() {
+    DCHECK(opened_);
+    read_index_ = write_index_ = 0;
+  }
+
+  virtual int Read(uint8* byte) {
+    DCHECK(byte);
+
+    if (read_index_ >= write_index_) {
+      return 0;
+    }
+    *byte = ring_buffer_[read_index_++];
+    if (read_index_ == BUFFER_SIZE)
+      read_index_ = 0;
+    return 1;
+  }
+
+  virtual int Write(scoped_refptr<net::IOBuffer> io_buffer, int byte_count) {
+    DCHECK(io_buffer.get());
+    DCHECK(byte_count >= 0);
+
+    char *data = io_buffer->data();
+    int count = byte_count;
+    while (count--) {
+      ring_buffer_[write_index_++] = *data++;
+      if (write_index_ == BUFFER_SIZE)
+        write_index_ = 0;
+    }
+    return byte_count;
+  }
+
+ private:
+  enum { BUFFER_SIZE = 256 };
+  bool opened_;
+  char ring_buffer_[BUFFER_SIZE];
+  int read_index_;
+  int write_index_;
+
+  DISALLOW_COPY_AND_ASSIGN(FakeEchoSerialConnection);
+};
+
+class FakeSerialOpenFunction : public SerialOpenFunction {
+ protected:
+  virtual SerialConnection* CreateSerialConnection(
+      const std::string& port,
+      int bitrate,
+      APIResourceEventNotifier* event_notifier) OVERRIDE {
+    return new FakeEchoSerialConnection(port, bitrate, event_notifier);
+  }
+  virtual bool DoesPortExist(const std::string& port) OVERRIDE {
+    return true;
+  }
+};
+
+}  // namespace extensions
+
+ExtensionFunction* FakeSerialGetPortsFunctionFactory() {
+  return new extensions::FakeSerialGetPortsFunction();
+}
+
+ExtensionFunction* FakeSerialOpenFunctionFactory() {
+  return new extensions::FakeSerialOpenFunction();
+}
+
+// Disable SIMULATE_SERIAL_PORTS only if all the following are true:
+//
+// 1. You have an Arduino or compatible board attached to your machine and
+// properly appearing as the first virtual serial port ("first" is very loosely
+// defined as whichever port shows up in serial.getPorts). We've tested only
+// the Atmega32u4 Breakout Board and Arduino Leonardo; note that both these
+// boards are based on the Atmel ATmega32u4, rather than the more common
+// Arduino '328p with either FTDI or '8/16u2 USB interfaces. TODO: test more
+// widely.
+//
+// 2. Your user has permission to read/write the port. For example, this might
+// mean that your user is in the "tty" or "uucp" group on Ubuntu flavors of
+// Linux, or else that the port's path (e.g., /dev/ttyACM0) has global
+// read/write permissions.
+//
+// 3. You have uploaded a program to the board that does a byte-for-byte echo
+// on the virtual serial port at 57600 bps. An example is at
+// chrome/test/data/extensions/api_test/serial/api/serial_arduino_test.ino.
+//
+#define SIMULATE_SERIAL_PORTS (1)
 IN_PROC_BROWSER_TEST_F(SerialApiTest, SerialExtension) {
   ResultCatcher catcher;
   catcher.RestrictToProfile(browser()->profile());
 
-  ExtensionTestMessageListener listener("serial_port", true);
-
-  ASSERT_TRUE(LoadExtension(test_data_dir_.AppendASCII("serial/api")));
-  EXPECT_TRUE(listener.WaitUntilSatisfied());
-
-#if 0
-  // Enable this path only if all the following are true:
-  //
-  // 1. You have an Arduino or compatible board attached to your machine and
-  // properly appearing as the first virtual serial port ("first" is very
-  // loosely defined as whichever port shows up in serial.getPorts). We've
-  // tested only the Atmega32u4 Breakout Board and Arduino Leonardo; note that
-  // both these boards are based on the Atmel ATmega32u4, rather than the more
-  // common Arduino '328p with either FTDI or '8/16u2 USB interfaces. TODO:
-  // test more widely.
-  //
-  // 2. Your user has permission to read/write the port. For example, this
-  // might mean that your user is in the "tty" or "uucp" group on Ubuntu
-  // flavors of Linux, or else that the port's path (e.g., /dev/ttyACM0) has
-  // global read/write permissions.
-  //
-  // 3. You have uploaded a program to the board that does a byte-for-byte echo
-  // on the virtual serial port at 57600 bps. An example is at
-  // chrome/test/data/extensions/api_test/serial/api/serial_arduino_test.ino.
-  //
-  listener.Reply("echo_device_attached");
-#else
-  listener.Reply("false");
+#if SIMULATE_SERIAL_PORTS
+  ASSERT_TRUE(ExtensionFunctionDispatcher::OverrideFunction(
+      "experimental.serial.getPorts",
+      FakeSerialGetPortsFunctionFactory));
+  ASSERT_TRUE(ExtensionFunctionDispatcher::OverrideFunction(
+      "experimental.serial.open",
+      FakeSerialOpenFunctionFactory));
 #endif
 
-  EXPECT_TRUE(catcher.GetNextResult()) << catcher.message();
+  ASSERT_TRUE(RunExtensionTest("serial/api")) << message_;
 }