dialect/sql: add tests for graph neighbors function

Summary: Pull Request resolved: https://github.com/facebookincubator/ent/pull/141

Reviewed By: naor9991

Differential Revision: D18333780

fbshipit-source-id: 920f1c77182ee2a5cbd942d6c9cceec448b9900b

dialect/sql/graph_test.go

@@ -0,0 +1,99 @@
+// Copyright 2019-present Facebook Inc. All rights reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+package sql
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestNeighbors(t *testing.T) {
+	tests := []struct {
+		name      string
+		input     *Step
+		wantQuery string
+		wantArgs  []interface{}
+	}{
+		{
+			name: "O2M/2types",
+			input: func() *Step {
+				step := &Step{}
+				step.From.V = 1
+				step.From.Table = "users"
+				step.From.Column = "id"
+				step.To.Table = "pets"
+				step.To.Column = "id"
+				step.Edge.Rel = O2M
+				step.Edge.Table = "pets"
+				step.Edge.Columns = []string{"owner_id"}
+				return step
+			}(),
+			wantQuery: "SELECT * FROM `pets` WHERE `owner_id` = ?",
+			wantArgs:  []interface{}{1},
+		},
+		{
+			name: "O2M/1type",
+			input: func() *Step {
+				step := &Step{}
+				step.From.V = 1
+				step.From.Table = "users"
+				step.From.Column = "id"
+				step.To.Table = "users"
+				step.To.Column = "id"
+				step.Edge.Rel = O2M
+				step.Edge.Table = "users"
+				step.Edge.Columns = []string{"parent_id"}
+				return step
+			}(),
+			wantQuery: "SELECT * FROM `users` WHERE `parent_id` = ?",
+			wantArgs:  []interface{}{1},
+		},
+		{
+			name: "M2O/2types/inverse",
+			input: func() *Step {
+				step := &Step{}
+				step.From.V = 2
+				step.From.Table = "pets"
+				step.From.Column = "id"
+				step.To.Table = "users"
+				step.To.Column = "id"
+				step.Edge.Rel = M2O
+				step.Edge.Inverse = true
+				step.Edge.Table = "pets"
+				step.Edge.Columns = []string{"owner_id"}
+				return step
+			}(),
+			wantQuery: "SELECT * FROM `users` JOIN (SELECT `owner_id` FROM `pets` WHERE `id` = ?) AS `t1` ON `users`.`id` = `t1`.`owner_id`",
+			wantArgs:  []interface{}{2},
+		},
+		{
+			name: "M2O/1type/inverse",
+			input: func() *Step {
+				step := &Step{}
+				step.From.V = 2
+				step.From.Table = "users"
+				step.From.Column = "id"
+				step.To.Table = "users"
+				step.To.Column = "id"
+				step.Edge.Rel = M2O
+				step.Edge.Inverse = true
+				step.Edge.Table = "users"
+				step.Edge.Columns = []string{"parent_id"}
+				return step
+			}(),
+			wantQuery: "SELECT * FROM `users` JOIN (SELECT `parent_id` FROM `users` WHERE `id` = ?) AS `t1` ON `users`.`id` = `t1`.`parent_id`",
+			wantArgs:  []interface{}{2},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			selector := Neighbors("", tt.input)
+			query, args := selector.Query()
+			require.Equal(t, tt.wantQuery, query)
+			require.Equal(t, tt.wantArgs, args)
+		})
+	}
+}