diff --git a/tests/src/test/resources/org/everit/json/schema/issues/issue21/schema.json b/tests/src/test/resources/org/everit/json/schema/issues/issue21/schema.json
new file mode 100644
index 000000000..6dc47a03c
--- /dev/null
+++ b/tests/src/test/resources/org/everit/json/schema/issues/issue21/schema.json
@@ -0,0 +1,21 @@
+{
+    "type":"object",
+    "$schema":"http://json-schema.org/draft-04/schema#",
+    "definitions":{
+        "language_object":{
+            "type":"object",
+            "additionalProperties":false,
+            "patternProperties":{
+                "^[a-z]{2}$":{
+                    "type":"string"
+                }
+            }
+        }
+    },
+    "properties":{
+        "name":{
+        	"$ref":"#/definitions/language_object",
+            "minProperties":1
+        }
+    }
+}
\ No newline at end of file
diff --git a/tests/src/test/resources/org/everit/json/schema/issues/issue21/subject-invalid.json b/tests/src/test/resources/org/everit/json/schema/issues/issue21/subject-invalid.json
new file mode 100644
index 000000000..d45293efe
--- /dev/null
+++ b/tests/src/test/resources/org/everit/json/schema/issues/issue21/subject-invalid.json
@@ -0,0 +1,3 @@
+{
+   "name":{}
+}
\ No newline at end of file