Improve with go code

README.md

@@ -1,6 +1,6 @@
 [![Go Reference](https://pkg.go.dev/badge/github.com/go-tstr/tstr.svg)](https://pkg.go.dev/github.com/go-tstr/tstr) [![codecov](https://codecov.io/github/go-tstr/tstr/graph/badge.svg?token=H3u7Ui9PfC)](https://codecov.io/github/go-tstr/tstr) ![main](https://github.com/go-tstr/tstr/actions/workflows/go.yaml/badge.svg?branch=main)
 
-# TSTR: your ultimate testing library!
+# tstr: your ultimate testing library
 
 tstr is testing library allows you to write integration and black-box tests like normal unit tests in Go.
 
@@ -151,7 +151,24 @@ func TestMain(m *testing.M) {
 
 #### Cmd
 
-Cmd dependecy is the most versatile one. It can be used for running any binary or even compiling a Go application and running it as dependency.
+Cmd dependecy is the most versatile dependency. It can be used for running any binary or even compiling a Go application and running it as dependency.
+
+##### cmd.WithCommand
+
+`cmd.WithCommand` allows using binaries from
+
+```go
+func TestMain(m *testing.M) {
+    tstr.RunMain(m, tstr.WithDeps(
+        cmd.New(
+            cmd.WithCommand("my-app", "--listen", ":8080"),
+            cmd.WithWaitMatchingLine("Server ready"),
+        ),
+    ))
+}
+```
+
+##### cmd.WithGoCode
 
 This example compiles `my-app` Go application, instruments it for coverage collections, waits for it to be ready and finally starts running tests.
 

dep/cmd/cmd.go

@@ -25,6 +25,7 @@
 	ErrBadRegexp      = strerr.Error("bad regular expression for matching line")
 	ErrOutputPipe     = strerr.Error("failed to aquire output pipe for command")
 	ErrBuildFailed    = strerr.Error("failed to build go binary")
+	ErrCreateCoverDir = strerr.Error("failed create coverage dir")
 )
 
 type Cmd struct {
@@ -49,7 +50,7 @@
 func (c *Cmd) Start() error {
 	for _, opt := range c.opts {
 		if err := opt(c); err != nil {
-			return fmt.Errorf("failed to apply option: %w", err)
+			return fmt.Errorf("%w: %w", ErrOptApply, err)
 		}
 	}
 
@@ -133,20 +134,20 @@
 	}
 }
 
-// WithEnv sets environment variables for the command.
-// By default, the command inherits the environment of the current process and setting this option will override it.
-func WithEnv(env ...string) Opt {
+// WithEnvSet sets environment variables for the command.
+// By default the command inherits the environment of the current process and setting this option will override it.
+func WithEnvSet(env ...string) Opt {
 	return func(c *Cmd) error {
 		c.cmd.Env = env
 		return nil
 	}
 }
 
 // WithEnvAppend adds environment variables to commands current env.
-// By default, the command inherits the environment of the current process and setting this option will override it.
+// By default the command inherits the environment of the current process and setting this option will override it.
 func WithEnvAppend(env ...string) Opt {
 	return func(c *Cmd) error {
-		c.cmd.Env = env
+		c.cmd.Env = append(c.cmd.Env, env...)
 		return nil
 	}
 }
@@ -229,6 +230,18 @@
 		}
 
 		c.cmd = exec.Command(target)
+		c.cmd.Stdout = os.Stdout
+		c.cmd.Stderr = os.Stderr
+		return nil
+	}
+}
+
+func WithGoCoverDir(dir string) Opt {
+	return func(c *Cmd) error {
+		if err := os.MkdirAll(dir, 0o755); err != nil {
+			return fmt.Errorf("%w: %w", ErrCreateCoverDir, err)
+		}
+		c.cmd.Env = append(c.cmd.Env, "GOCOVERDIR="+dir)
 		return nil
 	}
 }
@@ -259,6 +272,7 @@
 		return nil, fmt.Errorf("%w: %w", ErrBadRegexp, err)
 	}
 
+	cmd.Stdout = nil
 	stdout, err := cmd.StdoutPipe()
 	if err != nil {
 		return nil, fmt.Errorf("%w: %w", ErrOutputPipe, err)

dep/cmd/cmd_test.go

@@ -1,7 +1,6 @@
 package cmd_test
 
 import (
-	"bytes"
 	"net/http"
 	"net/http/httptest"
 	"os"
@@ -96,7 +95,16 @@ func TestCmd(t *testing.T) {
 			name: "WithEnv",
 			cmd: cmd.New(
 				cmd.WithCommand("go", "env", "GOPRIVATE"),
-				cmd.WithEnv("GOPRIVATE=foo"),
+				cmd.WithEnvSet("GOPRIVATE=foo"),
+				cmd.WithWaitMatchingLine("foo"),
+				cmd.WithStopFn(func(c *exec.Cmd) error { return nil }),
+			),
+		},
+		{
+			name: "WithEnv",
+			cmd: cmd.New(
+				cmd.WithCommand("go", "env", "GOPRIVATE"),
+				cmd.WithEnvAppend("GOPRIVATE=foo"),
 				cmd.WithWaitMatchingLine("foo"),
 				cmd.WithStopFn(func(c *exec.Cmd) error { return nil }),
 			),
@@ -147,18 +155,6 @@ func TestCmd(t *testing.T) {
 			),
 			err: cmd.ErrBadRegexp,
 		},
-		{
-			name: "StdoutPipeErr",
-			cmd: cmd.New(
-				cmd.WithExecCmd(func() *exec.Cmd {
-					c := exec.Command("go", "version")
-					c.Stdout = bytes.NewBuffer(nil)
-					return c
-				}()),
-				cmd.WithWaitMatchingLine("lol"),
-			),
-			err: cmd.ErrOutputPipe,
-		},
 		{
 			name: "WithGoCode_BuildFailure",
 			cmd: cmd.New(
@@ -195,7 +191,7 @@ func TestCmd_WithGoCode_Coverage(t *testing.T) {
 	c := cmd.New(
 		cmd.WithGoCode(waitPkg, "./"),
 		cmd.WithWaitMatchingLine("Waiting for signal"),
-		cmd.WithEnvAppend("GOCOVERDIR="+coverDir),
+		cmd.WithGoCoverDir(coverDir),
 	)
 	deptest.ErrorIs(t, c, nil, nil)