Format a line if a range in its leading whitespace was selected.

With [] marking the selected range, clang-format invoked on

    [  ]   int a;

Would so far not reformat anything. With this patch, it formats a
line if its leading whitespace is touched.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@176435 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/unittests/Format/FormatTest.cpp b/unittests/Format/FormatTest.cpp
index 8cedfce..46eb1bc 100644
--- a/unittests/Format/FormatTest.cpp
+++ b/unittests/Format/FormatTest.cpp
@@ -172,6 +172,28 @@
             format("int a;  \nint b;    ", 0, 0, getLLVMStyle()));
 }
 
+TEST_F(FormatTest, FormatsCorrectRegionForLeadingWhitespace) {
+  EXPECT_EQ("int b;\nint a;",
+            format("int b;\n   int a;", 7, 0, getLLVMStyle()));
+  EXPECT_EQ("int b;\n   int a;",
+            format("int b;\n   int a;", 6, 0, getLLVMStyle()));
+
+  EXPECT_EQ("#define A  \\\n"
+            "  int a;   \\\n"
+            "  int b;",
+            format("#define A  \\\n"
+                   "  int a;   \\\n"
+                   "    int b;",
+                   26, 0, getLLVMStyleWithColumns(12)));
+  EXPECT_EQ("#define A  \\\n"
+            "  int a;   \\\n"
+            "    int b;",
+            format("#define A  \\\n"
+                   "  int a;   \\\n"
+                   "    int b;",
+                   25, 0, getLLVMStyleWithColumns(12)));
+}
+
 TEST_F(FormatTest, ReformatsMovedLines) {
   EXPECT_EQ(
       "template <typename T> T *getFETokenInfo() const {\n"