clientconn_parsed_target_test.go - third_party/github.com/grpc/grpc-go - Git at Google

 /*
  *
  * Copyright 2021 gRPC authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *     http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  *
  */

 package grpc

 import (
 	"context"
 	"errors"
 	"fmt"
 	"net"
 	"net/url"
 	"testing"
 	"time"

 	"github.com/google/go-cmp/cmp"
 	"google.golang.org/grpc/credentials/insecure"
 	"google.golang.org/grpc/internal/testutils"

 	"google.golang.org/grpc/resolver"
 )

 func (s) TestParsedTarget_Success_WithoutCustomDialer(t *testing.T) {
 	defScheme := resolver.GetDefaultScheme()
 	tests := []struct {
 		target     string
 		badScheme  bool
 		wantParsed resolver.Target
 	}{
 		// No scheme is specified.
 		{target: "://", badScheme: true, wantParsed: resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, "://"))}},
 		{target: ":///", badScheme: true, wantParsed: resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, ":///"))}},
 		{target: "://a/", badScheme: true, wantParsed: resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, "://a/"))}},
 		{target: ":///a", badScheme: true, wantParsed: resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, ":///a"))}},
 		{target: "://a/b", badScheme: true, wantParsed: resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, "://a/b"))}},
 		{target: "/", badScheme: true, wantParsed: resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, "/"))}},
 		{target: "a/b", badScheme: true, wantParsed: resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, "a/b"))}},
 		{target: "a//b", badScheme: true, wantParsed: resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, "a//b"))}},
 		{target: "google.com", badScheme: true, wantParsed: resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, "google.com"))}},
 		{target: "google.com/?a=b", badScheme: true, wantParsed: resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, "google.com/?a=b"))}},
 		{target: "/unix/socket/address", badScheme: true, wantParsed: resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, "/unix/socket/address"))}},

 		// An unregistered scheme is specified.
 		{target: "a:///", badScheme: true, wantParsed: resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, "a:///"))}},
 		{target: "a://b/", badScheme: true, wantParsed: resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, "a://b/"))}},
 		{target: "a:///b", badScheme: true, wantParsed: resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, "a:///b"))}},
 		{target: "a://b/c", badScheme: true, wantParsed: resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, "a://b/c"))}},
 		{target: "a:b", badScheme: true, wantParsed: resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, "a:b"))}},
 		{target: "a:/b", badScheme: true, wantParsed: resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, "a:/b"))}},
 		{target: "a://b", badScheme: true, wantParsed: resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, "a://b"))}},

 		// A registered scheme is specified.
 		{target: "dns:///google.com", wantParsed: resolver.Target{Scheme: "dns", Authority: "", URL: *testutils.MustParseURL("dns:///google.com")}},
 		{target: "dns://a.server.com/google.com", wantParsed: resolver.Target{Scheme: "dns", Authority: "a.server.com", URL: *testutils.MustParseURL("dns://a.server.com/google.com")}},
 		{target: "dns://a.server.com/google.com/?a=b", wantParsed: resolver.Target{Scheme: "dns", Authority: "a.server.com", URL: *testutils.MustParseURL("dns://a.server.com/google.com/?a=b")}},
 		{target: "unix:///a/b/c", wantParsed: resolver.Target{Scheme: "unix", Authority: "", URL: *testutils.MustParseURL("unix:///a/b/c")}},
 		{target: "unix-abstract:a/b/c", wantParsed: resolver.Target{Scheme: "unix-abstract", Authority: "", URL: *testutils.MustParseURL("unix-abstract:a/b/c")}},
 		{target: "unix-abstract:a b", wantParsed: resolver.Target{Scheme: "unix-abstract", Authority: "", URL: *testutils.MustParseURL("unix-abstract:a b")}},
 		{target: "unix-abstract:a:b", wantParsed: resolver.Target{Scheme: "unix-abstract", Authority: "", URL: *testutils.MustParseURL("unix-abstract:a:b")}},
 		{target: "unix-abstract:a-b", wantParsed: resolver.Target{Scheme: "unix-abstract", Authority: "", URL: *testutils.MustParseURL("unix-abstract:a-b")}},
 		{target: "unix-abstract:/ a///://::!@#$%25^&*()b", wantParsed: resolver.Target{Scheme: "unix-abstract", Authority: "", URL: *testutils.MustParseURL("unix-abstract:/ a///://::!@#$%25^&*()b")}},
 		{target: "unix-abstract:passthrough:abc", wantParsed: resolver.Target{Scheme: "unix-abstract", Authority: "", URL: *testutils.MustParseURL("unix-abstract:passthrough:abc")}},
 		{target: "unix-abstract:unix:///abc", wantParsed: resolver.Target{Scheme: "unix-abstract", Authority: "", URL: *testutils.MustParseURL("unix-abstract:unix:///abc")}},
 		{target: "unix-abstract:///a/b/c", wantParsed: resolver.Target{Scheme: "unix-abstract", Authority: "", URL: *testutils.MustParseURL("unix-abstract:///a/b/c")}},
 		{target: "unix-abstract:///", wantParsed: resolver.Target{Scheme: "unix-abstract", Authority: "", URL: *testutils.MustParseURL("unix-abstract:///")}},
 		{target: "passthrough:///unix:///a/b/c", wantParsed: resolver.Target{Scheme: "passthrough", Authority: "", URL: *testutils.MustParseURL("passthrough:///unix:///a/b/c")}},

 		// Cases for `scheme:absolute-path`.
 		{target: "dns:/a/b/c", wantParsed: resolver.Target{Scheme: "dns", Authority: "", URL: *testutils.MustParseURL("dns:/a/b/c")}},
 		{target: "unregistered:/a/b/c", badScheme: true, wantParsed: resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL("unregistered:/a/b/c")}},
 	}

 	for _, test := range tests {
 		t.Run(test.target, func(t *testing.T) {
 			target := test.target
 			if test.badScheme {
 				target = defScheme + ":///" + target
 			}
 			url, err := url.Parse(target)
 			if err != nil {
 				t.Fatalf("Unexpected error parsing URL: %v", err)
 			}
 			test.wantParsed.URL = *url

 			cc, err := Dial(test.target, WithTransportCredentials(insecure.NewCredentials()))
 			if err != nil {
 				t.Fatalf("Dial(%q) failed: %v", test.target, err)
 			}
 			defer cc.Close()

 			if !cmp.Equal(cc.parsedTarget, test.wantParsed) {
 				t.Errorf("cc.parsedTarget for dial target %q = %+v, want %+v", test.target, cc.parsedTarget, test.wantParsed)
 			}
 		})
 	}
 }

 func (s) TestParsedTarget_Failure_WithoutCustomDialer(t *testing.T) {
 	targets := []string{
 		"",
 		"unix://a/b/c",
 		"unix://authority",
 		"unix-abstract://authority/a/b/c",
 		"unix-abstract://authority",
 	}

 	for _, target := range targets {
 		t.Run(target, func(t *testing.T) {
 			if cc, err := Dial(target, WithTransportCredentials(insecure.NewCredentials())); err == nil {
 				defer cc.Close()
 				t.Fatalf("Dial(%q) succeeded cc.parsedTarget = %+v, expected to fail", target, cc.parsedTarget)
 			}
 		})
 	}
 }

 func (s) TestParsedTarget_WithCustomDialer(t *testing.T) {
 	defScheme := resolver.GetDefaultScheme()
 	tests := []struct {
 		target            string
 		badScheme         bool
 		wantParsed        resolver.Target
 		wantDialerAddress string
 	}{
 		// unix:[local_path], unix:[/absolute], and unix://[/absolute] have
 		// different behaviors with a custom dialer.
 		{
 			target:            "unix:a/b/c",
 			wantParsed:        resolver.Target{Scheme: "unix", Authority: "", URL: *testutils.MustParseURL("unix:a/b/c")},
 			wantDialerAddress: "unix:a/b/c",
 		},
 		{
 			target:            "unix:/a/b/c",
 			wantParsed:        resolver.Target{Scheme: "unix", Authority: "", URL: *testutils.MustParseURL("unix:/a/b/c")},
 			wantDialerAddress: "unix:///a/b/c",
 		},
 		{
 			target:            "unix:///a/b/c",
 			wantParsed:        resolver.Target{Scheme: "unix", Authority: "", URL: *testutils.MustParseURL("unix:///a/b/c")},
 			wantDialerAddress: "unix:///a/b/c",
 		},
 		{
 			target:            "dns:///127.0.0.1:50051",
 			wantParsed:        resolver.Target{Scheme: "dns", Authority: "", URL: *testutils.MustParseURL("dns:///127.0.0.1:50051")},
 			wantDialerAddress: "127.0.0.1:50051",
 		},
 		{
 			target:            ":///127.0.0.1:50051",
 			badScheme:         true,
 			wantParsed:        resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, ":///127.0.0.1:50051"))},
 			wantDialerAddress: ":///127.0.0.1:50051",
 		},
 		{
 			target:            "dns://authority/127.0.0.1:50051",
 			wantParsed:        resolver.Target{Scheme: "dns", Authority: "authority", URL: *testutils.MustParseURL("dns://authority/127.0.0.1:50051")},
 			wantDialerAddress: "127.0.0.1:50051",
 		},
 		{
 			target:            "://authority/127.0.0.1:50051",
 			badScheme:         true,
 			wantParsed:        resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, "://authority/127.0.0.1:50051"))},
 			wantDialerAddress: "://authority/127.0.0.1:50051",
 		},
 		{
 			target:            "/unix/socket/address",
 			badScheme:         true,
 			wantParsed:        resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, "/unix/socket/address"))},
 			wantDialerAddress: "/unix/socket/address",
 		},
 		{
 			target:            "",
 			badScheme:         true,
 			wantParsed:        resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, ""))},
 			wantDialerAddress: "",
 		},
 		{
 			target:            "passthrough://a.server.com/google.com",
 			wantParsed:        resolver.Target{Scheme: "passthrough", Authority: "a.server.com", URL: *testutils.MustParseURL("passthrough://a.server.com/google.com")},
 			wantDialerAddress: "google.com",
 		},
 	}

 	for _, test := range tests {
 		t.Run(test.target, func(t *testing.T) {
 			target := test.target
 			if test.badScheme {
 				target = defScheme + ":///" + target
 			}
 			url, err := url.Parse(target)
 			if err != nil {
 				t.Fatalf("Unexpected error parsing URL: %v", err)
 			}
 			test.wantParsed.URL = *url

 			addrCh := make(chan string, 1)
 			dialer := func(ctx context.Context, address string) (net.Conn, error) {
 				addrCh <- address
 				return nil, errors.New("dialer error")
 			}

 			cc, err := Dial(test.target, WithTransportCredentials(insecure.NewCredentials()), WithContextDialer(dialer))
 			if err != nil {
 				t.Fatalf("Dial(%q) failed: %v", test.target, err)
 			}
 			defer cc.Close()

 			select {
 			case addr := <-addrCh:
 				if addr != test.wantDialerAddress {
 					t.Fatalf("address in custom dialer is %q, want %q", addr, test.wantDialerAddress)
 				}
 			case <-time.After(time.Second):
 				t.Fatal("timeout when waiting for custom dialer to be invoked")
 			}
 			if !cmp.Equal(cc.parsedTarget, test.wantParsed) {
 				t.Errorf("cc.parsedTarget for dial target %q = %+v, want %+v", test.target, cc.parsedTarget, test.wantParsed)
 			}
 		})
 	}
 }
	/*
	*
	* Copyright 2021 gRPC authors.
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*
	*/

	package grpc

	import (
	"context"
	"errors"
	"fmt"
	"net"
	"net/url"
	"testing"
	"time"

	"github.com/google/go-cmp/cmp"
	"google.golang.org/grpc/credentials/insecure"
	"google.golang.org/grpc/internal/testutils"

	"google.golang.org/grpc/resolver"
	)

	func (s) TestParsedTarget_Success_WithoutCustomDialer(t *testing.T) {
	defScheme := resolver.GetDefaultScheme()
	tests := []struct {
	target string
	badScheme bool
	wantParsed resolver.Target
	}{
	// No scheme is specified.
	{target: "://", badScheme: true, wantParsed: resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, "://"))}},
	{target: ":///", badScheme: true, wantParsed: resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, ":///"))}},
	{target: "://a/", badScheme: true, wantParsed: resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, "://a/"))}},
	{target: ":///a", badScheme: true, wantParsed: resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, ":///a"))}},
	{target: "://a/b", badScheme: true, wantParsed: resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, "://a/b"))}},
	{target: "/", badScheme: true, wantParsed: resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, "/"))}},
	{target: "a/b", badScheme: true, wantParsed: resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, "a/b"))}},
	{target: "a//b", badScheme: true, wantParsed: resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, "a//b"))}},
	{target: "google.com", badScheme: true, wantParsed: resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, "google.com"))}},
	{target: "google.com/?a=b", badScheme: true, wantParsed: resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, "google.com/?a=b"))}},
	{target: "/unix/socket/address", badScheme: true, wantParsed: resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, "/unix/socket/address"))}},

	// An unregistered scheme is specified.
	{target: "a:///", badScheme: true, wantParsed: resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, "a:///"))}},
	{target: "a://b/", badScheme: true, wantParsed: resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, "a://b/"))}},
	{target: "a:///b", badScheme: true, wantParsed: resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, "a:///b"))}},
	{target: "a://b/c", badScheme: true, wantParsed: resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, "a://b/c"))}},
	{target: "a:b", badScheme: true, wantParsed: resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, "a:b"))}},
	{target: "a:/b", badScheme: true, wantParsed: resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, "a:/b"))}},
	{target: "a://b", badScheme: true, wantParsed: resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, "a://b"))}},

	// A registered scheme is specified.
	{target: "dns:///google.com", wantParsed: resolver.Target{Scheme: "dns", Authority: "", URL: *testutils.MustParseURL("dns:///google.com")}},
	{target: "dns://a.server.com/google.com", wantParsed: resolver.Target{Scheme: "dns", Authority: "a.server.com", URL: *testutils.MustParseURL("dns://a.server.com/google.com")}},
	{target: "dns://a.server.com/google.com/?a=b", wantParsed: resolver.Target{Scheme: "dns", Authority: "a.server.com", URL: *testutils.MustParseURL("dns://a.server.com/google.com/?a=b")}},
	{target: "unix:///a/b/c", wantParsed: resolver.Target{Scheme: "unix", Authority: "", URL: *testutils.MustParseURL("unix:///a/b/c")}},
	{target: "unix-abstract:a/b/c", wantParsed: resolver.Target{Scheme: "unix-abstract", Authority: "", URL: *testutils.MustParseURL("unix-abstract:a/b/c")}},
	{target: "unix-abstract:a b", wantParsed: resolver.Target{Scheme: "unix-abstract", Authority: "", URL: *testutils.MustParseURL("unix-abstract:a b")}},
	{target: "unix-abstract:a:b", wantParsed: resolver.Target{Scheme: "unix-abstract", Authority: "", URL: *testutils.MustParseURL("unix-abstract:a:b")}},
	{target: "unix-abstract:a-b", wantParsed: resolver.Target{Scheme: "unix-abstract", Authority: "", URL: *testutils.MustParseURL("unix-abstract:a-b")}},
	{target: "unix-abstract:/ a///://::!@#$%25^&()b", wantParsed: resolver.Target{Scheme: "unix-abstract", Authority: "", URL: testutils.MustParseURL("unix-abstract:/ a///://::!@#$%25^&*()b")}},
	{target: "unix-abstract:passthrough:abc", wantParsed: resolver.Target{Scheme: "unix-abstract", Authority: "", URL: *testutils.MustParseURL("unix-abstract:passthrough:abc")}},
	{target: "unix-abstract:unix:///abc", wantParsed: resolver.Target{Scheme: "unix-abstract", Authority: "", URL: *testutils.MustParseURL("unix-abstract:unix:///abc")}},
	{target: "unix-abstract:///a/b/c", wantParsed: resolver.Target{Scheme: "unix-abstract", Authority: "", URL: *testutils.MustParseURL("unix-abstract:///a/b/c")}},
	{target: "unix-abstract:///", wantParsed: resolver.Target{Scheme: "unix-abstract", Authority: "", URL: *testutils.MustParseURL("unix-abstract:///")}},
	{target: "passthrough:///unix:///a/b/c", wantParsed: resolver.Target{Scheme: "passthrough", Authority: "", URL: *testutils.MustParseURL("passthrough:///unix:///a/b/c")}},

	// Cases for `scheme:absolute-path`.
	{target: "dns:/a/b/c", wantParsed: resolver.Target{Scheme: "dns", Authority: "", URL: *testutils.MustParseURL("dns:/a/b/c")}},
	{target: "unregistered:/a/b/c", badScheme: true, wantParsed: resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL("unregistered:/a/b/c")}},
	}

	for _, test := range tests {
	t.Run(test.target, func(t *testing.T) {
	target := test.target
	if test.badScheme {
	target = defScheme + ":///" + target
	}
	url, err := url.Parse(target)
	if err != nil {
	t.Fatalf("Unexpected error parsing URL: %v", err)
	}
	test.wantParsed.URL = *url

	cc, err := Dial(test.target, WithTransportCredentials(insecure.NewCredentials()))
	if err != nil {
	t.Fatalf("Dial(%q) failed: %v", test.target, err)
	}
	defer cc.Close()

	if !cmp.Equal(cc.parsedTarget, test.wantParsed) {
	t.Errorf("cc.parsedTarget for dial target %q = %+v, want %+v", test.target, cc.parsedTarget, test.wantParsed)
	}
	})
	}
	}

	func (s) TestParsedTarget_Failure_WithoutCustomDialer(t *testing.T) {
	targets := []string{
	"",
	"unix://a/b/c",
	"unix://authority",
	"unix-abstract://authority/a/b/c",
	"unix-abstract://authority",
	}

	for _, target := range targets {
	t.Run(target, func(t *testing.T) {
	if cc, err := Dial(target, WithTransportCredentials(insecure.NewCredentials())); err == nil {
	defer cc.Close()
	t.Fatalf("Dial(%q) succeeded cc.parsedTarget = %+v, expected to fail", target, cc.parsedTarget)
	}
	})
	}
	}

	func (s) TestParsedTarget_WithCustomDialer(t *testing.T) {
	defScheme := resolver.GetDefaultScheme()
	tests := []struct {
	target string
	badScheme bool
	wantParsed resolver.Target
	wantDialerAddress string
	}{
	// unix:[local_path], unix:[/absolute], and unix://[/absolute] have
	// different behaviors with a custom dialer.
	{
	target: "unix:a/b/c",
	wantParsed: resolver.Target{Scheme: "unix", Authority: "", URL: *testutils.MustParseURL("unix:a/b/c")},
	wantDialerAddress: "unix:a/b/c",
	},
	{
	target: "unix:/a/b/c",
	wantParsed: resolver.Target{Scheme: "unix", Authority: "", URL: *testutils.MustParseURL("unix:/a/b/c")},
	wantDialerAddress: "unix:///a/b/c",
	},
	{
	target: "unix:///a/b/c",
	wantParsed: resolver.Target{Scheme: "unix", Authority: "", URL: *testutils.MustParseURL("unix:///a/b/c")},
	wantDialerAddress: "unix:///a/b/c",
	},
	{
	target: "dns:///127.0.0.1:50051",
	wantParsed: resolver.Target{Scheme: "dns", Authority: "", URL: *testutils.MustParseURL("dns:///127.0.0.1:50051")},
	wantDialerAddress: "127.0.0.1:50051",
	},
	{
	target: ":///127.0.0.1:50051",
	badScheme: true,
	wantParsed: resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, ":///127.0.0.1:50051"))},
	wantDialerAddress: ":///127.0.0.1:50051",
	},
	{
	target: "dns://authority/127.0.0.1:50051",
	wantParsed: resolver.Target{Scheme: "dns", Authority: "authority", URL: *testutils.MustParseURL("dns://authority/127.0.0.1:50051")},
	wantDialerAddress: "127.0.0.1:50051",
	},
	{
	target: "://authority/127.0.0.1:50051",
	badScheme: true,
	wantParsed: resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, "://authority/127.0.0.1:50051"))},
	wantDialerAddress: "://authority/127.0.0.1:50051",
	},
	{
	target: "/unix/socket/address",
	badScheme: true,
	wantParsed: resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, "/unix/socket/address"))},
	wantDialerAddress: "/unix/socket/address",
	},
	{
	target: "",
	badScheme: true,
	wantParsed: resolver.Target{Scheme: defScheme, Authority: "", URL: *testutils.MustParseURL(fmt.Sprintf("%s:///%s", defScheme, ""))},
	wantDialerAddress: "",
	},
	{
	target: "passthrough://a.server.com/google.com",
	wantParsed: resolver.Target{Scheme: "passthrough", Authority: "a.server.com", URL: *testutils.MustParseURL("passthrough://a.server.com/google.com")},
	wantDialerAddress: "google.com",
	},
	}

	for _, test := range tests {
	t.Run(test.target, func(t *testing.T) {
	target := test.target
	if test.badScheme {
	target = defScheme + ":///" + target
	}
	url, err := url.Parse(target)
	if err != nil {
	t.Fatalf("Unexpected error parsing URL: %v", err)
	}
	test.wantParsed.URL = *url

	addrCh := make(chan string, 1)
	dialer := func(ctx context.Context, address string) (net.Conn, error) {
	addrCh <- address
	return nil, errors.New("dialer error")
	}

	cc, err := Dial(test.target, WithTransportCredentials(insecure.NewCredentials()), WithContextDialer(dialer))
	if err != nil {
	t.Fatalf("Dial(%q) failed: %v", test.target, err)
	}
	defer cc.Close()

	select {
	case addr := <-addrCh:
	if addr != test.wantDialerAddress {
	t.Fatalf("address in custom dialer is %q, want %q", addr, test.wantDialerAddress)
	}
	case <-time.After(time.Second):
	t.Fatal("timeout when waiting for custom dialer to be invoked")
	}
	if !cmp.Equal(cc.parsedTarget, test.wantParsed) {
	t.Errorf("cc.parsedTarget for dial target %q = %+v, want %+v", test.target, cc.parsedTarget, test.wantParsed)
	}
	})
	}
	}