1 files changed, 12 insertions, 0 deletions
diff --git a/spec/parcom_spec.cr b/spec/parcom_spec.cr
index efb3964..cee6ff4 100644
--- a/spec/parcom_spec.cr
+++ b/spec/parcom_spec.cr
@@ -278,6 +278,18 @@ describe Parser do
     end
   end
 
+  describe "#map_const" do
+    p = Parser(Char, Char).any_token
+    p_mapped = p.map_const(42)
+
+    tokens = Tokens.from_string("abcd")
+    result = p_mapped.parse(tokens)
+
+    it "changes the value of the result" do
+      result.value.should eq(42)
+    end
+  end
+
   describe "#|" do
     a = Parser(Char, Char).token('a')
     b = Parser(Char, Char).token('b')