Index: unittests/Format/FormatTest.cpp
===================================================================
--- unittests/Format/FormatTest.cpp
+++ unittests/Format/FormatTest.cpp
@@ -38,7 +38,8 @@
 
   std::string format(llvm::StringRef Code,
                      const FormatStyle &Style = getLLVMStyle(),
-                     StatusCheck CheckComplete = SC_ExpectComplete) {
+                     StatusCheck CheckComplete = SC_ExpectComplete,
+                     bool check = true) {
     LLVM_DEBUG(llvm::errs() << "---\n");
     LLVM_DEBUG(llvm::errs() << Code << "\n\n");
     std::vector<tooling::Range> Ranges(1, tooling::Range(0, Code.size()));
@@ -54,6 +55,12 @@
     auto Result = applyAllReplacements(Code, Replaces);
     EXPECT_TRUE(static_cast<bool>(Result));
     LLVM_DEBUG(llvm::errs() << "\n" << *Result << "\n\n");
+    if (check && Status.FormatComplete) {
+      // Do recursive call and check that format of format is valid.
+      LLVM_DEBUG(llvm::errs() << "\ncheck\n\n");
+      auto FormatedResult = format(*Result, Style, SC_ExpectComplete, false);
+      EXPECT_EQ(*Result, FormatedResult);
+    }
     return *Result;
   }