diff --git a/tests/test_assert.h b/tests/test_assert.h
index 883586b..353e3ce 100644
--- a/tests/test_assert.h
+++ b/tests/test_assert.h
@@ -13,20 +13,20 @@
   #define FLATBUFFERS_NO_FILE_TESTS
 #else
   #define TEST_OUTPUT_LINE(...) \
-      { printf(__VA_ARGS__); printf("\n"); }
+      do { printf(__VA_ARGS__); printf("\n"); } while(!IsConstTrue(true))
 #endif
 
-#define TEST_EQ(exp, val) TestEq(exp, val, #exp, __FILE__, __LINE__)
-#define TEST_ASSERT(exp) TestEq(exp, true, #exp, __FILE__, __LINE__)
-#define TEST_NOTNULL(exp) TestEq(exp == NULL, false, #exp, __FILE__, __LINE__)
-#define TEST_EQ_STR(exp, val) TestEqStr(exp, val, #exp, __FILE__, __LINE__)
+#define TEST_EQ(exp, val) TestEq(exp, val, "'" #exp "' != '" #val "'", __FILE__, __LINE__, "")
+#define TEST_ASSERT(val)  TestEq(true, !!(val), "'" "true" "' != '" #val "'", __FILE__, __LINE__, "")
+#define TEST_NOTNULL(val) TestEq(true, (val) != nullptr, "'" "nullptr" "' == '" #val "'", __FILE__, __LINE__, "")
+#define TEST_EQ_STR(exp, val) TestEqStr(exp, val, "'" #exp "' != '" #val "'", __FILE__, __LINE__, "")
 
 #ifdef _WIN32
-  #define TEST_ASSERT_FUNC(exp) TestEq(exp, true, #exp, __FILE__, __LINE__, __FUNCTION__)
-  #define TEST_EQ_FUNC(exp, val) TestEq(exp, val, #exp, __FILE__, __LINE__, __FUNCTION__)
+  #define TEST_ASSERT_FUNC(val) TestEq(true, !!(val), "'" "true" "' != '" #val "'", __FILE__, __LINE__, __FUNCTION__)
+  #define TEST_EQ_FUNC(exp, val) TestEq(exp, val, "'" #exp "' != '" #val "'", __FILE__, __LINE__, __FUNCTION__)
 #else
-  #define TEST_ASSERT_FUNC(exp) TestEq(exp, true, #exp, __FILE__, __LINE__, __PRETTY_FUNCTION__)
-  #define TEST_EQ_FUNC(exp, val) TestEq(exp, val, #exp, __FILE__, __LINE__, __PRETTY_FUNCTION__)
+  #define TEST_ASSERT_FUNC(val) TestEq(true, !!(val), "'" "true" "' != '" #val "'", __FILE__, __LINE__, __PRETTY_FUNCTION__)
+  #define TEST_EQ_FUNC(exp, val) TestEq(exp, val, "'" #exp "' != '" #val "'", __FILE__, __LINE__, __PRETTY_FUNCTION__)
 #endif
 
 // clang-format on
@@ -54,14 +54,55 @@
               const char *file, int line, const char *func = 0);
 
 void TestEqStr(const char *expval, const char *val, const char *exp,
-               const char *file, int line);
+               const char *file, int line, const char *func = 0);
+
+// Workaround for `enum class` printing.
+// There is an issue with the printing of enums with a fixed underlying type.
+// These enums are generated by `flatc` if `--scoped-enums` is active.
+// All modern compilers have problems with `std::stringstream&<<(T v)` if T is
+// an enum with fixed type. For details see DR1601:
+// http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#1601
+// https://stackoverflow.com/questions/34336024/ambiguous-overload-when-writing-an-enum-with-an-enum-base-but-only-with-clang
+
+template<typename T, bool is_enum_type = flatbuffers::is_enum<T>::value>
+struct underlying_of_scalar {
+  static_assert(flatbuffers::is_scalar<T>::value, "invalid type T");
+  typedef T type;
+};
+
+template<typename T> struct underlying_of_scalar<T, true> {
+// clang-format off
+  // There are old compilers without full C++11 support (see stl_emulation.h).
+  #if defined(FLATBUFFERS_TEMPLATES_ALIASES) && !defined(FLATBUFFERS_CPP98_STL)
+  using type = typename std::underlying_type<T>::type;
+  #else
+  typedef int64_t type;
+  #endif
+  // clang-format on
+};
+
+template<typename T>
+typename underlying_of_scalar<T>::type scalar_as_underlying(T v) {
+  return static_cast<typename underlying_of_scalar<T>::type>(v);
+}
 
 template<typename T, typename U>
 void TestEq(T expval, U val, const char *exp, const char *file, int line,
-            const char *func = 0) {
-  if (U(expval) != val) {
-    TestFail(flatbuffers::NumToString(expval).c_str(),
-             flatbuffers::NumToString(val).c_str(), exp, file, line, func);
+            const char *func) {
+  if (static_cast<U>(expval) != val) {
+    TestFail(flatbuffers::NumToString(scalar_as_underlying(expval)).c_str(),
+             flatbuffers::NumToString(scalar_as_underlying(val)).c_str(), exp,
+             file, line, func);
+  }
+}
+
+template<>
+inline void TestEq<std::string, std::string>(std::string expval,
+                                             std::string val, const char *exp,
+                                             const char *file, int line,
+                                             const char *func) {
+  if (expval != val) {
+    TestFail(expval.c_str(), val.c_str(), exp, file, line, func);
   }
 }