Make the format scrambler understand line comments.

This allows for writing tests including line comments easier and more readable.
We will need more of those tests in the future and also line comments are
useful to force line breaks in tests.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@170446 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/unittests/Format/FormatTest.cpp b/unittests/Format/FormatTest.cpp
index bcac37c..fef56ca 100644
--- a/unittests/Format/FormatTest.cpp
+++ b/unittests/Format/FormatTest.cpp
@@ -40,22 +40,35 @@
     return format(Code, 0, Code.size(), Style);
   }
 
-  void verifyFormat(llvm::StringRef Code) {
-    std::string WithoutFormat(Code.str());
-    for (unsigned i = 0, e = WithoutFormat.size(); i != e; ++i) {
-      if (WithoutFormat[i] == '\n')
-        WithoutFormat[i] = ' ';
+  std::string messUp(llvm::StringRef Code) {
+    std::string MessedUp(Code.str());
+    bool InComment = false;
+    bool JustReplacedNewline = false;
+    for (unsigned i = 0, e = MessedUp.size() - 1; i != e; ++i) {
+      if (MessedUp[i] == '/' && MessedUp[i + 1] == '/') {
+        if (JustReplacedNewline)
+          MessedUp[i - 1] = '\n';
+        InComment = true;
+      } else if (MessedUp[i] != ' ') {
+        JustReplacedNewline = false;
+      } else if (MessedUp[i] == '\n') {
+        if (InComment) {
+          InComment = false;
+        } else {
+          JustReplacedNewline = true;
+          MessedUp[i] = ' ';
+        }
+      }
     }
-    EXPECT_EQ(Code.str(), format(WithoutFormat));
+    return MessedUp;
+  }
+
+  void verifyFormat(llvm::StringRef Code) {
+    EXPECT_EQ(Code.str(), format(messUp(Code)));
   }
 
   void verifyGoogleFormat(llvm::StringRef Code) {
-    std::string WithoutFormat(Code.str());
-    for (unsigned i = 0, e = WithoutFormat.size(); i != e; ++i) {
-      if (WithoutFormat[i] == '\n')
-        WithoutFormat[i] = ' ';
-    }
-    EXPECT_EQ(Code.str(), format(WithoutFormat, getGoogleStyle()));
+    EXPECT_EQ(Code.str(), format(messUp(Code), getGoogleStyle()));
   }
 };
 
@@ -96,7 +109,9 @@
   verifyFormat("if (true)\n  f();\ng();");
   verifyFormat("if (a)\n  if (b)\n    if (c)\n      g();\nh();");
   verifyFormat("if (a)\n  if (b) {\n    f();\n  }\ng();");
-  EXPECT_EQ("if (a)\n  // comment\n  f();", format("if(a)\n// comment\nf();"));
+  verifyFormat("if (a)\n"
+               "  // comment\n"
+               "  f();");
 }
 
 TEST_F(FormatTest, ParseIfElse) {
@@ -236,21 +251,22 @@
 //===----------------------------------------------------------------------===//
 
 TEST_F(FormatTest, UnderstandsSingleLineComments) {
-  EXPECT_EQ("// line 1\n// line 2\nvoid f() {\n}\n",
-            format("// line 1\n// line 2\nvoid f() {}\n"));
+  verifyFormat("// line 1\n"
+               "// line 2\n"
+               "void f() {\n}\n");
 
-  EXPECT_EQ("void f() {\n  // Doesn't do anything\n}",
-            format("void f() {\n// Doesn't do anything\n}"));
+  verifyFormat("void f() {\n"
+               "  // Doesn't do anything\n"
+               "}");
 
-  EXPECT_EQ("int i  // This is a fancy variable\n    = 5;",
-            format("int i  // This is a fancy variable\n= 5;"));
+  verifyFormat("int i  // This is a fancy variable\n"
+               "    = 5;");
 
-  EXPECT_EQ("enum E {\n"
-            "  // comment\n"
-            "  VAL_A,  // comment\n"
-            "  VAL_B\n"
-            "};",
-            format("enum E{\n// comment\nVAL_A,// comment\nVAL_B};"));
+  verifyFormat("enum E {\n"
+               "  // comment\n"
+               "  VAL_A,  // comment\n"
+               "  VAL_B\n"
+               "};");
 
   verifyFormat(
       "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa =\n"