diff --git a/clang/unittests/Frontend/CompilerInvocationTest.cpp b/clang/unittests/Frontend/CompilerInvocationTest.cpp
index 0eb76a13972c19..7712dd00b191ca 100644
--- a/clang/unittests/Frontend/CompilerInvocationTest.cpp
+++ b/clang/unittests/Frontend/CompilerInvocationTest.cpp
@@ -8,6 +8,7 @@
 
 #include "clang/Frontend/CompilerInvocation.h"
 #include "clang/Frontend/CompilerInstance.h"
+#include "clang/Frontend/TextDiagnosticBuffer.h"
 #include "llvm/Support/Host.h"
 
 #include "gmock/gmock.h"
@@ -32,7 +33,9 @@ class CommandLineTest : public ::testing::Test {
   }
 
   CommandLineTest()
-      : Diags(CompilerInstance::createDiagnostics(new DiagnosticOptions())) {}
+      : Diags(CompilerInstance::createDiagnostics(new DiagnosticOptions(),
+                                                  new TextDiagnosticBuffer())) {
+  }
 };
 
 TEST_F(CommandLineTest, OptIsInitializedWithCustomDefaultValue) {
@@ -40,6 +43,8 @@ TEST_F(CommandLineTest, OptIsInitializedWithCustomDefaultValue) {
 
   CompilerInvocation::CreateFromArgs(Invocation, Args, *Diags);
 
+  ASSERT_FALSE(Diags->hasErrorOccurred());
+
   ASSERT_TRUE(Invocation.getFrontendOpts().UseTemporary);
 }
 
@@ -48,6 +53,8 @@ TEST_F(CommandLineTest, OptOfNegativeFlagIsPopulatedWithFalse) {
 
   CompilerInvocation::CreateFromArgs(Invocation, Args, *Diags);
 
+  ASSERT_FALSE(Diags->hasErrorOccurred());
+
   ASSERT_FALSE(Invocation.getFrontendOpts().UseTemporary);
 }
 
@@ -56,6 +63,8 @@ TEST_F(CommandLineTest, OptsOfImpliedPositiveFlagArePopulatedWithTrue) {
 
   CompilerInvocation::CreateFromArgs(Invocation, Args, *Diags);
 
+  ASSERT_FALSE(Diags->hasErrorOccurred());
+
   // Explicitly provided flag.
   ASSERT_TRUE(Invocation.getLangOpts()->CLUnsafeMath);
 
@@ -72,6 +81,8 @@ TEST_F(CommandLineTest, CanGenerateCC1CommandLineFlag) {
 
   CompilerInvocation::CreateFromArgs(Invocation, Args, *Diags);
 
+  ASSERT_FALSE(Diags->hasErrorOccurred());
+
   Invocation.generateCC1CommandLine(GeneratedArgs, *this);
 
   ASSERT_THAT(GeneratedArgs, Contains(StrEq("-fmodules-strict-context-hash")));
@@ -83,6 +94,8 @@ TEST_F(CommandLineTest, CanGenerateCC1CommandLineSeparate) {
 
   CompilerInvocation::CreateFromArgs(Invocation, Args, *Diags);
 
+  ASSERT_FALSE(Diags->hasErrorOccurred());
+
   Invocation.generateCC1CommandLine(GeneratedArgs, *this);
 
   ASSERT_THAT(GeneratedArgs, Contains(StrEq(TripleCStr)));
@@ -95,6 +108,8 @@ TEST_F(CommandLineTest,  CanGenerateCC1CommandLineSeparateRequiredPresent) {
 
   CompilerInvocation::CreateFromArgs(Invocation, Args, *Diags);
 
+  ASSERT_FALSE(Diags->hasErrorOccurred());
+
   Invocation.generateCC1CommandLine(GeneratedArgs, *this);
 
   // Triple should always be emitted even if it is the default
@@ -108,6 +123,8 @@ TEST_F(CommandLineTest, CanGenerateCC1CommandLineSeparateRequiredAbsent) {
 
   CompilerInvocation::CreateFromArgs(Invocation, Args, *Diags);
 
+  ASSERT_FALSE(Diags->hasErrorOccurred());
+
   Invocation.generateCC1CommandLine(GeneratedArgs, *this);
 
   // Triple should always be emitted even if it is the default
@@ -119,6 +136,8 @@ TEST_F(CommandLineTest, CanGenerateCC1CommandLineSeparateEnumNonDefault) {
 
   CompilerInvocation::CreateFromArgs(Invocation, Args, *Diags);
 
+  ASSERT_FALSE(Diags->hasErrorOccurred());
+
   Invocation.generateCC1CommandLine(GeneratedArgs, *this);
 
   // Non default relocation model.
@@ -130,6 +149,8 @@ TEST_F(CommandLineTest, CanGenerateCC1COmmandLineSeparateEnumDefault) {
 
   CompilerInvocation::CreateFromArgs(Invocation, Args, *Diags);
 
+  ASSERT_FALSE(Diags->hasErrorOccurred());
+
   Invocation.generateCC1CommandLine(GeneratedArgs, *this);
 
   // Default relocation model.
@@ -141,6 +162,8 @@ TEST_F(CommandLineTest, NotPresentNegativeFlagNotGenerated) {
 
   CompilerInvocation::CreateFromArgs(Invocation, Args, *Diags);
 
+  ASSERT_FALSE(Diags->hasErrorOccurred());
+
   Invocation.generateCC1CommandLine(GeneratedArgs, *this);
 
   ASSERT_THAT(GeneratedArgs, Not(Contains(StrEq("-fno-temp-file"))));
@@ -151,6 +174,8 @@ TEST_F(CommandLineTest, PresentNegativeFlagGenerated) {
 
   CompilerInvocation::CreateFromArgs(Invocation, Args, *Diags);
 
+  ASSERT_FALSE(Diags->hasErrorOccurred());
+
   Invocation.generateCC1CommandLine(GeneratedArgs, *this);
 
   ASSERT_THAT(GeneratedArgs, Contains(StrEq("-fno-temp-file")));
@@ -161,6 +186,8 @@ TEST_F(CommandLineTest, NotPresentAndNotImpliedNotGenerated) {
 
   CompilerInvocation::CreateFromArgs(Invocation, Args, *Diags);
 
+  ASSERT_FALSE(Diags->hasErrorOccurred());
+
   Invocation.generateCC1CommandLine(GeneratedArgs, *this);
 
   // Missing options are not generated.
@@ -175,6 +202,8 @@ TEST_F(CommandLineTest, NotPresentAndImpliedNotGenerated) {
 
   CompilerInvocation::CreateFromArgs(Invocation, Args, *Diags);
 
+  ASSERT_FALSE(Diags->hasErrorOccurred());
+
   Invocation.generateCC1CommandLine(GeneratedArgs, *this);
 
   // Missing options that were implied are not generated.
@@ -189,6 +218,8 @@ TEST_F(CommandLineTest, PresentAndImpliedNotGenerated) {
 
   CompilerInvocation::CreateFromArgs(Invocation, Args, *Diags);
 
+  ASSERT_FALSE(Diags->hasErrorOccurred());
+
   Invocation.generateCC1CommandLine(GeneratedArgs, *this);
 
   // Present options that were also implied are not generated.
@@ -202,6 +233,8 @@ TEST_F(CommandLineTest, PresentAndNotImpliedGenerated) {
 
   CompilerInvocation::CreateFromArgs(Invocation, Args, *Diags);
 
+  ASSERT_FALSE(Diags->hasErrorOccurred());
+
   Invocation.generateCC1CommandLine(GeneratedArgs, *this);
 
   // Present options that were not implied are generated.