diff --git a/lrpar/cttests/src/ctfails/warnings.test b/lrpar/cttests/src/ctfails/warnings.test
new file mode 100644
index 000000000..6b4c28c3f
--- /dev/null
+++ b/lrpar/cttests/src/ctfails/warnings.test
@@ -0,0 +1,12 @@
+name: Test warnings are treated as errors by default.
+yacckind: Original(YaccOriginalActionKind::GenericParseTree)
+grammar: |
+    %start A
+    %token b
+    %%
+    A : 'a';
+    B : 'b';
+lexer: |
+    %%
+    a 'a'
+    b 'b'
diff --git a/lrpar/cttests/src/ctfails/warnings_flags.test b/lrpar/cttests/src/ctfails/warnings_flags.test
new file mode 100644
index 000000000..14e586a7c
--- /dev/null
+++ b/lrpar/cttests/src/ctfails/warnings_flags.test
@@ -0,0 +1,13 @@
+name: Test enabling warnings are errors.
+yacckind: Original(YaccOriginalActionKind::GenericParseTree)
+yacc_flags: [ warnings_are_errors ]
+grammar: |
+    %start A
+    %token b
+    %%
+    A : 'a';
+    B : 'b';
+lexer: |
+    %%
+    a 'a'
+    b 'b'