diff --git a/test/Makefile b/test/Makefile
index c5a26ab..b0b9699 100644
--- a/test/Makefile
+++ b/test/Makefile
@@ -10,7 +10,7 @@ CC = clang
 endif
 ifeq ($(findstring clang, $(CC)), clang)
 E = -Weverything
-CFLAGS += $E -Wno-unknown-warning-option -Wno-missing-prototypes
+CFLAGS += $E -Wno-unknown-warning-option
 CFLAGS += -Wno-unsafe-buffer-usage
 endif
 CFLAGS += -std=c99 -pedantic -Wall -Wextra -Werror
diff --git a/test/tests/self_assessment_utils.h b/test/tests/self_assessment_utils.h
index f764ca9..24b755f 100644
--- a/test/tests/self_assessment_utils.h
+++ b/test/tests/self_assessment_utils.h
@@ -72,6 +72,11 @@ static char putcharSpyBuffer[SPY_BUFFER_MAX];
 static UNITY_COUNTER_TYPE indexSpyBuffer;
 static UNITY_COUNTER_TYPE putcharSpyEnabled;
 
+#ifdef __clang__
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wmissing-prototypes"
+#endif
+
 void startPutcharSpy(void)
 {
     indexSpyBuffer = 0;
@@ -133,6 +138,10 @@ void flushSpy(void)
     if (flushSpyEnabled){ flushSpyCalls++; }
 }
 
+#ifdef __clang__
+#pragma clang diagnostic pop
+#endif
+
 #define TEST_ASSERT_EQUAL_PRINT_NUMBERS(expected, actual) do {          \
         startPutcharSpy(); UnityPrintNumber((actual)); endPutcharSpy(); \
         TEST_ASSERT_EQUAL_STRING((expected), getBufferPutcharSpy());    \
@@ -149,3 +158,10 @@ void flushSpy(void)
         } while (0)
 
 #endif
+
+// The reason this isn't folded into the above diagnostic is to semi-isolate
+// the header contents from the user content it is included into.
+#ifdef __clang__
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wmissing-prototypes"
+#endif