[clang-format] In tests, expected code should be format-stable

Summary: Extend various verifyFormat helper functions to check that the
expected text is "stable". This provides some protection against bugs
where formatting results are ocilating between two forms, or continually
change in some other way.

Testing Done:

* Ran unit tests.

* Reproduced a known instability in preprocessor indentation which was
  caught by this new check.

Reviewers: krasimir

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D42034

llvm-svn: 329231

7 files changed, 11 insertions, 0 deletions

diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index 2d20bc03651..43225304670 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -72,6 +72,8 @@ protected:
 
   void verifyFormat(llvm::StringRef Expected, llvm::StringRef Code,
                     const FormatStyle &Style = getLLVMStyle()) {
+    EXPECT_EQ(Expected.str(), format(Expected, Style))
+        << "Expected code is not stable";
     EXPECT_EQ(Expected.str(), format(Code, Style));
     if (Style.Language == FormatStyle::LK_Cpp) {
       // Objective-C++ is a superset of C++, so everything checked for C++
diff --git a/clang/unittests/Format/FormatTestComments.cpp b/clang/unittests/Format/FormatTestComments.cpp
index ed11fbdb1fc..005039698bb 100644
--- a/clang/unittests/Format/FormatTestComments.cpp
+++ b/clang/unittests/Format/FormatTestComments.cpp
@@ -70,6 +70,7 @@ protected:
 
   void verifyFormat(llvm::StringRef Code,
                     const FormatStyle &Style = getLLVMStyle()) {
+    EXPECT_EQ(Code.str(), format(Code, Style)) << "Expected code is not stable";
     EXPECT_EQ(Code.str(), format(test::messUp(Code), Style));
   }
 
diff --git a/clang/unittests/Format/FormatTestJS.cpp b/clang/unittests/Format/FormatTestJS.cpp
index 5fb47a7d32f..347118353e3 100644
--- a/clang/unittests/Format/FormatTestJS.cpp
+++ b/clang/unittests/Format/FormatTestJS.cpp
@@ -49,6 +49,8 @@ protected:
   static void verifyFormat(
       llvm::StringRef Code,
       const FormatStyle &Style = getGoogleStyle(FormatStyle::LK_JavaScript)) {
+    EXPECT_EQ(Code.str(), format(Code, Style))
+        << "Expected code is not stable";
     std::string Result = format(test::messUp(Code), Style);
     EXPECT_EQ(Code.str(), Result) << "Formatted:\n" << Result;
   }
@@ -57,6 +59,8 @@ protected:
       llvm::StringRef Expected,
       llvm::StringRef Code,
       const FormatStyle &Style = getGoogleStyle(FormatStyle::LK_JavaScript)) {
+    EXPECT_EQ(Expected.str(), format(Expected, Style))
+        << "Expected code is not stable";
     std::string Result = format(Code, Style);
     EXPECT_EQ(Expected.str(), Result) << "Formatted:\n" << Result;
   }
diff --git a/clang/unittests/Format/FormatTestJava.cpp b/clang/unittests/Format/FormatTestJava.cpp
index 1d471b73ee6..36b72fda475 100644
--- a/clang/unittests/Format/FormatTestJava.cpp
+++ b/clang/unittests/Format/FormatTestJava.cpp
@@ -46,6 +46,7 @@ protected:
   static void verifyFormat(
       llvm::StringRef Code,
       const FormatStyle &Style = getGoogleStyle(FormatStyle::LK_Java)) {
+    EXPECT_EQ(Code.str(), format(Code, Style)) << "Expected code is not stable";
     EXPECT_EQ(Code.str(), format(test::messUp(Code), Style));
   }
 };
diff --git a/clang/unittests/Format/FormatTestObjC.cpp b/clang/unittests/Format/FormatTestObjC.cpp
index ed5d1aa2560..b54b1c0b63d 100644
--- a/clang/unittests/Format/FormatTestObjC.cpp
+++ b/clang/unittests/Format/FormatTestObjC.cpp
@@ -58,6 +58,7 @@ protected:
   }
 
   void verifyFormat(StringRef Code) {
+    EXPECT_EQ(Code.str(), format(Code)) << "Expected code is not stable";
     EXPECT_EQ(Code.str(), format(test::messUp(Code)));
   }
 
diff --git a/clang/unittests/Format/FormatTestProto.cpp b/clang/unittests/Format/FormatTestProto.cpp
index 66c5d3778d4..672fd5914d0 100644
--- a/clang/unittests/Format/FormatTestProto.cpp
+++ b/clang/unittests/Format/FormatTestProto.cpp
@@ -38,6 +38,7 @@ protected:
   }
 
   static void verifyFormat(llvm::StringRef Code) {
+    EXPECT_EQ(Code.str(), format(Code)) << "Expected code is not stable";
     EXPECT_EQ(Code.str(), format(test::messUp(Code)));
   }
 };
diff --git a/clang/unittests/Format/FormatTestTextProto.cpp b/clang/unittests/Format/FormatTestTextProto.cpp
index f4e09cf9e27..2cd7fb7bdf3 100644
--- a/clang/unittests/Format/FormatTestTextProto.cpp
+++ b/clang/unittests/Format/FormatTestTextProto.cpp
@@ -36,6 +36,7 @@ protected:
   }
 
   static void verifyFormat(llvm::StringRef Code, const FormatStyle &Style) {
+    EXPECT_EQ(Code.str(), format(Code, Style)) << "Expected code is not stable";
     EXPECT_EQ(Code.str(), format(test::messUp(Code), Style));
   }