add additional helper functions for setting command's environment

Author: rainu

builder_command.go

@@ -108,6 +108,13 @@ func (c *chain) WithInjections(sources ...io.Reader) CommandBuilder {
 	return c
 }
 
+func (c *chain) WithEmptyEnvironment() CommandBuilder {
+	cmdDesc := c.cmdDescriptors[len(c.cmdDescriptors)-1]
+	cmdDesc.command.Env = []string{}
+
+	return c
+}
+
 func (c *chain) WithEnvironmentMap(envMap map[interface{}]interface{}) CommandBuilder {
 	cmdDesc := c.cmdDescriptors[len(c.cmdDescriptors)-1]
 
@@ -127,6 +134,17 @@ func (c *chain) WithEnvironment(envMap ...interface{}) CommandBuilder {
 	for i := 0; i < len(envMap); i += 2 {
 		cmdDesc.command.Env = append(cmdDesc.command.Env, fmt.Sprintf("%v=%v", envMap[i], envMap[i+1]))
 	}
+
+	return c
+}
+
+func (c *chain) WithEnvironmentPairs(envMap ...string) CommandBuilder {
+	cmdDesc := c.cmdDescriptors[len(c.cmdDescriptors)-1]
+
+	for _, entry := range envMap {
+		cmdDesc.command.Env = append(cmdDesc.command.Env, entry)
+	}
+
 	return c
 }
 
@@ -148,6 +166,18 @@ func (c *chain) WithAdditionalEnvironment(envMap ...interface{}) CommandBuilder
 	return c.WithEnvironment(envMap...)
 }
 
+func (c *chain) WithAdditionalEnvironmentPairs(envMap ...string) CommandBuilder {
+	cmdDesc := c.cmdDescriptors[len(c.cmdDescriptors)-1]
+	pairs := cmdDesc.command.Env
+
+	if len(pairs) == 0 {
+		pairs = os.Environ()
+	}
+	pairs = append(pairs, envMap...)
+
+	return c.WithEnvironmentPairs(pairs...)
+}
+
 func (c *chain) WithWorkingDirectory(workingDir string) CommandBuilder {
 	cmdDesc := c.cmdDescriptors[len(c.cmdDescriptors)-1]
 	cmdDesc.command.Dir = workingDir

chain_test.go

@@ -292,6 +292,19 @@ func TestSimple_WithMultiInput(t *testing.T) {
 	runAndCompare(t, toTest, "2\n")
 }
 
+func TestSimple_WithProcessEnvironment(t *testing.T) {
+	chainWithEnv := Builder().Join(testHelper, "-pe")
+	chainWithoutEnv := Builder().Join(testHelper, "-pe").WithEmptyEnvironment()
+
+	out1, _, err := chainWithEnv.Finalize().RunAndGet()
+	assert.NoError(t, err)
+
+	out2, _, err := chainWithoutEnv.Finalize().RunAndGet()
+	assert.NoError(t, err)
+
+	assert.NotEqual(t, out1, out2)
+}
+
 func TestSimple_WithEnvironment(t *testing.T) {
 	toTest := Builder().
 		Join(testHelper, "-pe").WithEnvironment("TEST", "VALUE", "TEST2", 2)
@@ -307,6 +320,14 @@ func TestSimple_WithEnvironmentMap(t *testing.T) {
 	runAndCompare(t, toTest, "GO_COMMAND_CHAIN_TEST2=2\nGO_COMMAND_CHAIN_TEST=VALUE\n")
 }
 
+func TestSimple_WithEnvironmentPairs(t *testing.T) {
+	toTest := Builder().
+		Join(testHelper, "-pe").WithEnvironmentPairs("GO_COMMAND_CHAIN_TEST=VALUE", "GO_COMMAND_CHAIN_TEST2=2").
+		Join("sort")
+
+	runAndCompare(t, toTest, "GO_COMMAND_CHAIN_TEST2=2\nGO_COMMAND_CHAIN_TEST=VALUE\n")
+}
+
 func TestSimple_WithAdditionalEnvironment(t *testing.T) {
 	toTest := Builder().
 		Join(testHelper, "-pe").WithAdditionalEnvironment("GO_COMMAND_CHAIN_TEST", "VALUE", "GO_COMMAND_CHAIN_TEST2", 2).
@@ -325,6 +346,15 @@ func TestSimple_WithAdditionalEnvironmentMap(t *testing.T) {
 	runAndCompare(t, toTest, "GO_COMMAND_CHAIN_TEST2=2\nGO_COMMAND_CHAIN_TEST=VALUE\n")
 }
 
+func TestSimple_WithAdditionalEnvironmentPairs(t *testing.T) {
+	toTest := Builder().
+		Join(testHelper, "-pe").WithAdditionalEnvironmentPairs("GO_COMMAND_CHAIN_TEST=VALUE", "GO_COMMAND_CHAIN_TEST2=2").
+		Join("grep", "GO_COMMAND_CHAIN_TEST").
+		Join("sort")
+
+	runAndCompare(t, toTest, "GO_COMMAND_CHAIN_TEST2=2\nGO_COMMAND_CHAIN_TEST=VALUE\n")
+}
+
 func TestSimple_WithAdditionalEnvironment_butNotProcessEnv(t *testing.T) {
 	cmd := exec.Command(testHelper, "-pe")
 	cmd.Env = []string{"TEST=VALUE"}
@@ -345,6 +375,16 @@ func TestSimple_WithAdditionalEnvironmentMap_butNotProcessEnv(t *testing.T) {
 	runAndCompare(t, toTest, "TEST=VALUE\nTEST2=2\n")
 }
 
+func TestSimple_WithAdditionalEnvironmentPairs_butNotProcessEnv(t *testing.T) {
+	cmd := exec.Command(testHelper, "-pe")
+	cmd.Env = []string{"TEST=VALUE"}
+
+	toTest := Builder().
+		JoinCmd(cmd).WithAdditionalEnvironmentPairs("TEST2=2")
+
+	runAndCompare(t, toTest, "TEST=VALUE\nTEST2=2\n")
+}
+
 func TestSimple_WithEnvironment_InvalidArguments(t *testing.T) {
 	err := Builder().
 		Join(testHelper, "-pe").WithEnvironment("TEST", "VALUE", "TEST2").

interfaces.go

@@ -109,6 +109,10 @@ type CommandBuilder interface {
 	// If this behavior is not wanted, me the io.MultiReader is a better choice.
 	WithInjections(sources ...io.Reader) CommandBuilder
 
+	// WithEmptyEnvironment will use an empty environment for the previously joined command. The default behavior is to
+	// use the current process's environment.
+	WithEmptyEnvironment() CommandBuilder
+
 	// WithEnvironment will configure the previously joined command to use the given environment variables. Key-value
 	// pair(s) must be passed as arguments. Where the first represents the key and the second the value of the
 	// environment variable.
@@ -117,6 +121,10 @@ type CommandBuilder interface {
 	// WithEnvironmentMap will configure the previously joined command to use the given environment variables.
 	WithEnvironmentMap(envMap map[interface{}]interface{}) CommandBuilder
 
+	// WithEnvironmentPairs will configure the previously joined command to use the given environment variables.
+	// Each entry must have the form "key=value"
+	WithEnvironmentPairs(envMap ...string) CommandBuilder
+
 	// WithAdditionalEnvironment will do almost the same thing as WithEnvironment expecting that the given key-value
 	// pairs will be joined with the environment variables of the current process.
 	WithAdditionalEnvironment(envMap ...interface{}) CommandBuilder
@@ -125,6 +133,10 @@ type CommandBuilder interface {
 	// values will be joined with the environment variables of the current process.
 	WithAdditionalEnvironmentMap(envMap map[interface{}]interface{}) CommandBuilder
 
+	// WithAdditionalEnvironmentPairs will do almost the same thing as WithEnvironmentPairs expecting that the given
+	// values will be joined with the environment variables of the current process.
+	WithAdditionalEnvironmentPairs(envMap ...string) CommandBuilder
+
 	// WithWorkingDirectory will configure the previously joined command to use the specifies the working directory.
 	// Without setting the working directory, the calling process's current directory will be used.
 	WithWorkingDirectory(workingDir string) CommandBuilder