diff --git a/clang-tools-extra/clangd/index/Symbol.h b/clang-tools-extra/clangd/index/Symbol.h
--- a/clang-tools-extra/clangd/index/Symbol.h
+++ b/clang-tools-extra/clangd/index/Symbol.h
@@ -233,6 +233,8 @@
   std::vector<Symbol> Symbols;  // Sorted by SymbolID to allow lookup.
 };
 
+llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const SymbolSlab &Slab);
+
 } // namespace clangd
 } // namespace clang
 
diff --git a/clang-tools-extra/clangd/index/Symbol.cpp b/clang-tools-extra/clangd/index/Symbol.cpp
--- a/clang-tools-extra/clangd/index/Symbol.cpp
+++ b/clang-tools-extra/clangd/index/Symbol.cpp
@@ -67,5 +67,15 @@
   return SymbolSlab(std::move(NewArena), std::move(SortedSymbols));
 }
 
+llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const SymbolSlab &Slab) {
+  OS << "{";
+  llvm::StringRef Sep = "";
+  for (const auto &S : Slab) {
+    OS << Sep << S;
+    Sep = ", ";
+  }
+  OS << "}";
+  return OS;
+}
 } // namespace clangd
 } // namespace clang
diff --git a/clang-tools-extra/clangd/unittests/TestTU.cpp b/clang-tools-extra/clangd/unittests/TestTU.cpp
--- a/clang-tools-extra/clangd/unittests/TestTU.cpp
+++ b/clang-tools-extra/clangd/unittests/TestTU.cpp
@@ -17,7 +17,9 @@
 #include "clang/Frontend/CompilerInvocation.h"
 #include "clang/Frontend/Utils.h"
 #include "llvm/ADT/ScopeExit.h"
-#include "gtest/gtest.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/ScopedPrinter.h"
+#include "llvm/Support/raw_ostream.h"
 
 namespace clang {
 namespace clangd {
@@ -69,14 +71,15 @@
 
 void initializeModuleCache(CompilerInvocation &CI) {
   llvm::SmallString<128> ModuleCachePath;
-  ASSERT_FALSE(
-      llvm::sys::fs::createUniqueDirectory("module-cache", ModuleCachePath));
+  if (llvm::sys::fs::createUniqueDirectory("module-cache", ModuleCachePath))
+    llvm_unreachable("Failed to create temp directory for module-cache");
   CI.getHeaderSearchOpts().ModuleCachePath = ModuleCachePath.c_str();
 }
 
 void deleteModuleCache(const std::string ModuleCachePath) {
   if (!ModuleCachePath.empty()) {
-    ASSERT_FALSE(llvm::sys::fs::remove_directories(ModuleCachePath));
+    if (llvm::sys::fs::remove_directories(ModuleCachePath))
+      llvm_unreachable("Failed to delete temp directory for module-cache");
   }
 }
 
@@ -112,12 +115,12 @@
   auto AST = ParsedAST::build(testPath(Filename), Inputs, std::move(CI),
                               Diags.take(), Preamble);
   if (!AST.hasValue()) {
-    ADD_FAILURE() << "Failed to build code:\n" << Code;
+    llvm::errs() << "Failed to build code:\n" << Code;
     llvm_unreachable("Failed to build TestTU!");
   }
   if (!AST->getDiagnostics()) {
-    ADD_FAILURE() << "TestTU should always build an AST with a fresh Preamble"
-                  << Code;
+    llvm::errs() << "TestTU should always build an AST with a fresh Preamble"
+                 << Code;
     return std::move(*AST);
   }
   // Check for error diagnostics and report gtest failures (unless expected).
@@ -138,7 +141,7 @@
     // We always build AST with a fresh preamble in TestTU.
     for (const auto &D : *AST->getDiagnostics())
       if (D.Severity >= DiagnosticsEngine::Error) {
-        ADD_FAILURE()
+        llvm::errs()
             << "TestTU failed to build (suppress with /*error-ok*/): \n"
             << D << "\n\nFor code:\n"
             << Code;
@@ -176,16 +179,16 @@
     if (QName != (S.Scope + S.Name).str())
       continue;
     if (Result) {
-      ADD_FAILURE() << "Multiple symbols named " << QName << ":\n"
-                    << *Result << "\n---\n"
-                    << S;
+      llvm::errs() << "Multiple symbols named " << QName << ":\n"
+                   << *Result << "\n---\n"
+                   << S;
       assert(false && "QName is not unique");
     }
     Result = &S;
   }
   if (!Result) {
-    ADD_FAILURE() << "No symbol named " << QName << " in "
-                  << ::testing::PrintToString(Slab);
+    llvm::errs() << "No symbol named " << QName << " in "
+                 << llvm::to_string(Slab);
     assert(false && "No symbol with QName");
   }
   return *Result;
@@ -225,7 +228,7 @@
   Visitor.F = Filter;
   Visitor.TraverseDecl(AST.getASTContext().getTranslationUnitDecl());
   if (Visitor.Decls.size() != 1) {
-    ADD_FAILURE() << Visitor.Decls.size() << " symbols matched.";
+    llvm::errs() << Visitor.Decls.size() << " symbols matched.";
     assert(Visitor.Decls.size() == 1);
   }
   return *Visitor.Decls.front();