test: Add test to confirm ASSERT will return 500 Internal Server Error

Co-authored-by: Dmitry Wagin <dmitry.wagin@ya.ru>

test/Feature/RpcSpec.hs

@@ -494,6 +494,11 @@ spec actualPgVersion =
         liftIO $ do
           simpleStatus p `shouldBe` badRequest400
           isErrorFormat (simpleBody p) `shouldBe` True
+      it "treats plpgsql assert as internal server error" $ do
+        p <- post "/rpc/assert" "{}"
+        liftIO $ do
+          simpleStatus p `shouldBe` internalServerError500
+          isErrorFormat (simpleBody p) `shouldBe` True
 
     context "unsupported verbs" $ do
       it "DELETE fails" $