Add query error test

Author: tailhook

tests/query_errors.rs

@@ -0,0 +1,21 @@
+extern crate graphql_parser;
+#[cfg(test)] #[macro_use] extern crate pretty_assertions;
+
+use std::io::Read;
+use std::fs::File;
+
+use graphql_parser::parse_query;
+
+fn test_error(filename: &str) {
+    let mut buf = String::with_capacity(1024);
+    let path = format!("tests/query_errors/{}.txt", filename);
+    let mut f = File::open(&path).unwrap();
+    f.read_to_string(&mut buf).unwrap();
+    let mut iter = buf.splitn(2, "\n---\n");
+    let graphql = iter.next().unwrap();
+    let expected = iter.next().expect("file should contain error message");
+    let err = parse_query(&graphql).unwrap_err();
+    assert_eq!(err.to_string(), expected);
+}
+
+#[test] fn invalid_curly_brace() { test_error("invalid_curly_brace"); }

tests/query_errors/invalid_curly_brace.txt

@@ -0,0 +1,7 @@
+querry MyQuery {
+  field1
+}
+---
+query parse error: Parse error at 1:1
+Unexpected `querry[Name]`
+Expected `{`, `query`, `mutation`, `subscription` or `fragment`