[clang-format] Make NamespaceEndCommentFixer add at most one comment

Summary:
Until now, NamespaceEndCommentFixer was adding missing comments for every run,
which results in multiple end comments for:
```
namespace {
  int i;
  int j;
}
#if A
  int a = 1;
#else
  int a = 2;
#endif
```
result before:

```
namespace {
  int i;
  int j;
}// namespace // namespace
#if A
  int a = 1;
#else
  int a = 2;
#endif
```
result after:
```
namespace {
  int i;
  int j;
}// namespace
#if A
  int a = 1;
#else
  int a = 2;
#endif
```

Reviewers: djasper

Reviewed By: djasper

Subscribers: klimek, cfe-commits

Differential Revision: https://reviews.llvm.org/D30659

llvm-svn: 297028

1 files changed, 18 insertions, 0 deletions

diff --git a/clang/unittests/Format/NamespaceEndCommentsFixerTest.cpp b/clang/unittests/Format/NamespaceEndCommentsFixerTest.cpp
index 28212f8524d..0341fd7ef44 100644
--- a/clang/unittests/Format/NamespaceEndCommentsFixerTest.cpp
+++ b/clang/unittests/Format/NamespaceEndCommentsFixerTest.cpp
@@ -388,6 +388,24 @@ TEST_F(NamespaceEndCommentsFixerTest,
                                     "  int i;\n"
                                     "}\n"
                                     "}\n"));
+  EXPECT_EQ("namespace {\n"
+            "  int i;\n"
+            "  int j;\n"
+            "}// namespace\n"
+            "#if A\n"
+            "  int i;\n"
+            "#else\n"
+            "  int j;\n"
+            "#endif",
+            fixNamespaceEndComments("namespace {\n"
+                                    "  int i;\n"
+                                    "  int j;\n"
+                                    "}\n"
+                                    "#if A\n"
+                                    "  int i;\n"
+                                    "#else\n"
+                                    "  int j;\n"
+                                    "#endif"));
 }
 
 TEST_F(NamespaceEndCommentsFixerTest,