test: add TestGraphQLParseSchemaDuration() to better test larger schemas

Author: robmyersrobmyers

Diff for: v1/topdown/graphql_test.go

@@ -8,7 +8,9 @@ import (
 	"context"
 	"fmt"
 	"os"
+	"strings"
 	"testing"
+	"time"
 
 	"github.com/open-policy-agent/opa/v1/ast"
 	"github.com/open-policy-agent/opa/v1/topdown/cache"
@@ -889,3 +891,74 @@ func TestGraphQLParseSchema(t *testing.T) {
 		})
 	}
 }
+
+func TestGraphQLParseSchemaDuration(t *testing.T) {
+
+	maxDuration, _ := time.ParseDuration("10s")
+	t.Parallel()
+
+	cases := []struct {
+		note     string
+		schema   *ast.Term
+		duration time.Duration
+	}{
+		{
+			note:     "default schema",
+			schema:   ast.NewTerm(ast.String(employeeGQLSchema)),
+			duration: maxDuration,
+		},
+		{
+			note:     "default schema plus 100 additional types",
+			schema:   ast.NewTerm(ast.String(bigSchema(100))),
+			duration: maxDuration,
+		},
+		{
+			note:     "default schema plus 1,000 additional types",
+			schema:   ast.NewTerm(ast.String(bigSchema(1000))),
+			duration: maxDuration,
+		},
+		// Uncomment when https://github.com/open-policy-agent/opa/pull/7509 is merged
+		//{
+		//	note:     "default schema plus 10,000 additional types",
+		//	schema:   ast.NewTerm(ast.String(bigSchema(10000))),
+		//	duration: maxDuration,
+		//},
+	}
+
+	for _, tc := range cases {
+
+		t.Run(tc.note, func(t *testing.T) {
+			t.Parallel()
+			start := time.Now()
+			_ = builtinGraphQLParseSchema(
+				BuiltinContext{
+					InterQueryBuiltinValueCache: nil,
+				},
+				[]*ast.Term{tc.schema},
+				func(term *ast.Term) error {
+					return nil
+				},
+			)
+			finish := time.Now()
+			elapsedTime := finish.Sub(start)
+			if tc.duration < elapsedTime {
+				t.Errorf("Parsing schema '%s' cannot exceed %s, but took %s", tc.note, tc.duration, elapsedTime)
+				return
+			}
+		})
+	}
+}
+
+// Inflate GraphQL schema size with `count` extra types
+func bigSchema(count int) string {
+
+	// build up `count` more types on basic schema
+	var builder strings.Builder
+	builder.WriteString(employeeGQLSchema)
+
+	for range count {
+		fmt.Fprintf(&builder, "\ntype Employee%d {\n    id: String!\n    salary: Int!\n}\n", count)
+	}
+
+	return builder.String()
+}