Windows, subprocesses: add test for arg passing

Add an integration test to assert that
subprocesses created with WindowsSubprocessFactory
receive arguments as intended.

Next steps:
- implement the same argument escaping logic in
  Bazel as windowsEscapeArg2 in bazelbuild#7411
- replace WindowsProcesses.quoteCommandLine with
  the new escaper

See bazelbuild#7122

src/test/java/com/google/devtools/build/lib/BUILD

@@ -514,6 +514,7 @@ java_test(
     srcs = WINDOWS_ON_WINDOWS_TESTS,
     data = [
         ":MockSubprocess_deploy.jar",
+        ":printarg",
     ] + JNI_LIB,
     jvm_flags = [
         "-Dbazel.windows_unix_root=C:/fake/msys",
@@ -536,6 +537,12 @@ java_test(
     ],
 )
 
+cc_binary(
+    name = "printarg",
+    testonly = 1,
+    srcs = ["windows/printarg.cc"],
+)
+
 java_library(
     name = "actions_testutil",
     testonly = 1,

src/test/java/com/google/devtools/build/lib/windows/WindowsSubprocessTest.java

@@ -15,6 +15,7 @@
 package com.google.devtools.build.lib.windows;
 
 import static com.google.common.truth.Truth.assertThat;
+import static java.nio.charset.StandardCharsets.UTF_8;
 
 import com.google.common.collect.ImmutableMap;
 import com.google.devtools.build.lib.shell.Subprocess;
@@ -23,7 +24,7 @@
 import com.google.devtools.build.lib.util.OS;
 import com.google.devtools.build.runfiles.Runfiles;
 import java.io.File;
-import java.nio.charset.Charset;
+import java.util.Arrays;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
@@ -36,14 +37,14 @@
 @RunWith(JUnit4.class)
 @TestSpec(localOnly = true, supportedOs = OS.WINDOWS)
 public class WindowsSubprocessTest {
-  private static final Charset UTF8 = Charset.forName("UTF-8");
   private String mockSubprocess;
   private String mockBinary;
   private Subprocess process;
+  private Runfiles runfiles;
 
   @Before
   public void loadJni() throws Exception {
-    Runfiles runfiles = Runfiles.create();
+    runfiles = Runfiles.create();
     mockSubprocess =
         runfiles.rlocation(
             "io_bazel/src/test/java/com/google/devtools/build/lib/MockSubprocess_deploy.jar");
@@ -73,7 +74,7 @@ public void testSystemRootIsSetByDefault() throws Exception {
 
     byte[] buf = new byte[11];
     process.getInputStream().read(buf);
-    assertThat(new String(buf, UTF8).trim()).isEqualTo(System.getenv("SYSTEMROOT").trim());
+    assertThat(new String(buf, UTF_8).trim()).isEqualTo(System.getenv("SYSTEMROOT").trim());
   }
 
   @Test
@@ -88,7 +89,7 @@ public void testSystemDriveIsSetByDefault() throws Exception {
 
     byte[] buf = new byte[3];
     process.getInputStream().read(buf);
-    assertThat(new String(buf, UTF8).trim()).isEqualTo(System.getenv("SYSTEMDRIVE").trim());
+    assertThat(new String(buf, UTF_8).trim()).isEqualTo(System.getenv("SYSTEMDRIVE").trim());
   }
 
   @Test
@@ -105,7 +106,7 @@ public void testSystemRootIsSet() throws Exception {
 
     byte[] buf = new byte[16];
     process.getInputStream().read(buf);
-    assertThat(new String(buf, UTF8).trim()).isEqualTo("C:\\MySystemRoot");
+    assertThat(new String(buf, UTF_8).trim()).isEqualTo("C:\\MySystemRoot");
   }
 
   @Test
@@ -122,6 +123,52 @@ public void testSystemDriveIsSet() throws Exception {
 
     byte[] buf = new byte[3];
     process.getInputStream().read(buf);
-    assertThat(new String(buf, UTF8).trim()).isEqualTo("X:");
+    assertThat(new String(buf, UTF_8).trim()).isEqualTo("X:");
+  }
+
+  private static final class StringPair {
+    public final String first;
+    public final String second;
+
+    public StringPair(String first, String second) {
+      this.first = first;
+      this.second = second;
+    }
+  };
+
+  private void assertSubprocessReceivesArgsAsIntended(StringPair... args) throws Exception {
+    // Look up the path of the printarg.exe utility.
+    String printArgExe =
+        runfiles.rlocation("io_bazel/src/test/java/com/google/devtools/build/lib/printarg.exe");
+    assertThat(printArgExe).isNotEmpty();
+
+    // For each argument in 'args', create a separate subprocess.
+    for (StringPair arg : args) {
+      SubprocessBuilder subprocessBuilder = new SubprocessBuilder();
+      subprocessBuilder.setWorkingDirectory(new File("."));
+      subprocessBuilder.setSubprocessFactory(WindowsSubprocessFactory.INSTANCE);
+      subprocessBuilder.setArgv(printArgExe, arg.first);
+      process = subprocessBuilder.start();
+      process.waitFor();
+      assertThat(process.exitValue()).isEqualTo(0);
+
+      byte[] buf = new byte[1000];
+      process.getInputStream().read(buf);
+      String actual = new String(buf, UTF_8).trim();
+      assertThat(actual).isEqualTo("(" + arg.first + ")");
+    }
+  }
+
+  @Test
+  public void testSubprocessReceivesArgsAsIntended() throws Exception {
+    assertSubprocessReceivesArgsAsIntended(
+            new StringPair("", "\"\""),
+            new StringPair(" ", "\" \""),
+            new StringPair("foo", "foo"),
+            new StringPair("foo\\bar", "foo\\bar"),
+            new StringPair("foo bar", "\"foo bar\""));
+    // TODO(laszlocsomor): the escaping logic in WindowsProcesses.quoteCommandLine is wrong, because
+    // it fails to properly escape things like a single backslash followed by a quote, e.g. a\"b
+    // Fix the escaping logic and add more test here.
   }
 }

src/test/java/com/google/devtools/build/lib/windows/printarg.cc

@@ -0,0 +1,20 @@
+// Copyright 2019 The Bazel Authors. All rights reserved.
+//
+// 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.
+
+#include <stdio.h>
+
+int main(int argc, char** argv) {
+  printf("(%s)", argv[1]);
+  return 0;
+}