diff --git a/cmd/protoc-gen-connect-go/main_test.go b/cmd/protoc-gen-connect-go/main_test.go
new file mode 100644
index 00000000..17a2b9b2
--- /dev/null
+++ b/cmd/protoc-gen-connect-go/main_test.go
@@ -0,0 +1,126 @@
+// Copyright 2021-2024 The Connect 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 main
+
+import (
+	"bytes"
+	"io"
+	"os"
+	"os/exec"
+	"testing"
+
+	"connectrpc.com/connect"
+	"connectrpc.com/connect/internal/assert"
+	pingv1 "connectrpc.com/connect/internal/gen/connect/ping/v1"
+	"google.golang.org/protobuf/proto"
+	"google.golang.org/protobuf/reflect/protodesc"
+	"google.golang.org/protobuf/types/descriptorpb"
+	"google.golang.org/protobuf/types/pluginpb"
+)
+
+func TestVersion(t *testing.T) {
+	t.Parallel()
+	stdout, stderr, exitCode := testRunProtocGenGo(t, nil, "--version")
+	assert.Equal(t, stdout.String(), connect.Version+"\n")
+	assert.Equal(t, stderr.String(), "")
+	assert.Equal(t, exitCode, 0)
+}
+
+func TestGenerate(t *testing.T) {
+	t.Parallel()
+	pingFileDesc := protodesc.ToFileDescriptorProto(pingv1.File_connect_ping_v1_ping_proto)
+	compilerVersion := &pluginpb.Version{
+		Major:  ptr(int32(0)),
+		Minor:  ptr(int32(0)),
+		Patch:  ptr(int32(1)),
+		Suffix: ptr("test"),
+	}
+
+	t.Run("ping.proto", func(t *testing.T) {
+		t.Parallel()
+		req := &pluginpb.CodeGeneratorRequest{
+			FileToGenerate:        []string{"connect/ping/v1/ping.proto"},
+			Parameter:             nil,
+			ProtoFile:             []*descriptorpb.FileDescriptorProto{pingFileDesc},
+			SourceFileDescriptors: []*descriptorpb.FileDescriptorProto{pingFileDesc},
+			CompilerVersion:       compilerVersion,
+		}
+		rsp := testGenerate(t, req)
+		assert.Nil(t, rsp.Error)
+
+		assert.Equal(t, rsp.GetSupportedFeatures(), 3)
+		assert.Equal(t, rsp.GetMinimumEdition(), int32(descriptorpb.Edition_EDITION_PROTO2))
+		assert.Equal(t, rsp.GetMaximumEdition(), int32(descriptorpb.Edition_EDITION_2023))
+
+		assert.Equal(t, len(rsp.File), 1)
+		file := rsp.File[0]
+		assert.Equal(t, file.GetName(), "connectrpc.com/connect/internal/gen/connect/ping/v1/pingv1connect/ping.connect.go")
+		assert.NotZero(t, file.GetContent())
+	})
+	t.Run("ping.proto:same_package=true", func(t *testing.T) {
+		t.Parallel()
+		req := &pluginpb.CodeGeneratorRequest{
+			FileToGenerate:        []string{"connect/ping/v1/ping.proto"},
+			Parameter:             ptr("same_package=true"),
+			ProtoFile:             []*descriptorpb.FileDescriptorProto{pingFileDesc},
+			SourceFileDescriptors: []*descriptorpb.FileDescriptorProto{pingFileDesc},
+			CompilerVersion:       compilerVersion,
+		}
+		rsp := testGenerate(t, req)
+		assert.Nil(t, rsp.Error)
+
+		assert.Equal(t, len(rsp.File), 1)
+		file := rsp.File[0]
+		assert.Equal(t, file.GetName(), "connectrpc.com/connect/internal/gen/connect/ping/v1/ping.connect.go")
+		assert.NotZero(t, file.GetContent())
+	})
+}
+
+func testGenerate(t *testing.T, req *pluginpb.CodeGeneratorRequest) *pluginpb.CodeGeneratorResponse {
+	t.Helper()
+
+	inputBytes, err := proto.Marshal(req)
+	assert.Nil(t, err)
+
+	stdout, stderr, exitCode := testRunProtocGenGo(t, bytes.NewReader(inputBytes))
+	assert.Equal(t, exitCode, 0)
+	assert.Equal(t, stderr.String(), "")
+	assert.True(t, len(stdout.Bytes()) > 0)
+
+	var output pluginpb.CodeGeneratorResponse
+	assert.Nil(t, proto.Unmarshal(stdout.Bytes(), &output))
+	return &output
+}
+
+func testRunProtocGenGo(t *testing.T, stdin io.Reader, args ...string) (stdout, stderr *bytes.Buffer, exitCode int) {
+	t.Helper()
+
+	stdout = &bytes.Buffer{}
+	stderr = &bytes.Buffer{}
+	args = append([]string{"run", "main.go"}, args...)
+
+	cmd := exec.Command("go", args...)
+	cmd.Env = os.Environ()
+	cmd.Stdin = stdin
+	cmd.Stdout = stdout
+	cmd.Stderr = stderr
+	assert.Nil(t, cmd.Run(), assert.Sprintf("Run go %v", args))
+	exitCode = cmd.ProcessState.ExitCode()
+	return stdout, stderr, exitCode
+}
+
+func ptr[T any](v T) *T {
+	return &v
+}