add fuzzing for schema and query parsing

Author: João Veiga

go.mod

@@ -1,5 +1,8 @@
 module github.com/graph-gophers/graphql-go
 
-require github.com/opentracing/opentracing-go v1.1.0
+require (
+	github.com/opentracing/opentracing-go v1.1.0
+	github.com/stretchr/testify v1.3.0 // indirect
+)
 
 go 1.13

go.sum

@@ -1,2 +1,9 @@
+github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/opentracing/opentracing-go v1.1.0 h1:pWlfV3Bxv7k65HYwkikxat0+s3pV4bsqf19k25Ur8rU=
 github.com/opentracing/opentracing-go v1.1.0/go.mod h1:UkNAQd3GIcIGf0SeVgPpRdFStlNbqXla1AfSYxPUl2o=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.3.0 h1:TivCn/peBQ7UY8ooIcPgZFpTNSz0Q2U6UrFlUfqbe0Q=
+github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=

internal/query/query_test.go

@@ -0,0 +1,12 @@
+package query
+
+import (
+	"testing"
+)
+
+func FuzzParseQuery(f *testing.F) {
+    f.Fuzz(func(t *testing.T, queryStr string) {
+        Parse(queryStr)
+    })
+}
+

internal/schema/schema_test.go

@@ -1007,3 +1007,10 @@ func TestInterfaceImplementsInterface(t *testing.T) {
 		})
 	}
 }
+
+func FuzzParse(f *testing.F){
+	f.Fuzz(func(t *testing.T, schemaString string, useStringDescriptions bool){
+		s := schema.New()
+		schema.Parse(s, schemaString, useStringDescriptions)
+	})
+}