chore(tests): Add python layer contributor tests

Signed-off-by: Andrew Meyer <[email protected]>

buildpacks/python/cmd/main/main.go

@@ -16,6 +16,6 @@ func main() {
 	logger := bard.NewLogger(os.Stdout)
 	libpak.Main(
 		python.Detect{Logger: logger},
-		python.Build{Logger: logger},
+		python.Build{Logger: logger, CommandRunner: python.NewDefaultCommandRunner()},
 	)
 }

buildpacks/python/go.mod

@@ -4,6 +4,7 @@ go 1.19
 
 require (
 	github.com/buildpacks/libcnb v1.26.0
+	github.com/golang/mock v1.6.0
 	github.com/onsi/gomega v1.20.2
 	github.com/paketo-buildpacks/libpak v1.61.0
 	github.com/sclevine/spec v1.4.0

buildpacks/python/python/build.go

@@ -13,7 +13,8 @@ import (
 )
 
 type Build struct {
-	Logger bard.Logger
+	Logger        bard.Logger
+	CommandRunner CommandRunner
 }
 
 func (b Build) Build(context libcnb.BuildContext) (libcnb.BuildResult, error) {
@@ -49,12 +50,12 @@ func (b Build) Build(context libcnb.BuildContext) (libcnb.BuildResult, error) {
 		return libcnb.BuildResult{}, fmt.Errorf("unable to find dependency\n%w", err)
 	}
 
-	invokerDepCacheLayer := NewInvokerDependencyCache(invokerDeps, dependencyCache)
+	invokerDepCacheLayer := NewInvokerDependencyCache(invokerDeps, dependencyCache, b.CommandRunner)
 	invokerDepCacheLayer.Logger = b.Logger
-	result.Layers = append(result.Layers, &invokerDepCacheLayer)
+	result.Layers = append(result.Layers, invokerDepCacheLayer)
 
 	invokerLayer := NewInvoker(invoker, dependencyCache)
-	result.Layers = append(result.Layers, &invokerLayer)
+	result.Layers = append(result.Layers, invokerLayer)
 
 	functionPlan, ok, err := planResolver.Resolve("python-function")
 	if err != nil {
@@ -74,8 +75,9 @@ func (b Build) Build(context libcnb.BuildContext) (libcnb.BuildResult, error) {
 
 	validationLayer := NewFunctionValidationLayer(
 		context.Application.Path,
-		&invokerLayer,
-		&invokerDepCacheLayer,
+		invokerLayer,
+		invokerDepCacheLayer,
+		b.CommandRunner,
 		WithValidationLogger(b.Logger),
 		WithValidationFunctionClass(functionClass, isFuncDefDefault),
 		WithValidationFunctionEnvs(functionPlan.Metadata["func_yaml_envs"].(map[string]any)),

buildpacks/python/python/command_runner.go

@@ -0,0 +1,24 @@
+// Copyright 2021-2022 VMware, Inc.
+// SPDX-License-Identifier: BSD-2-Clause
+
+package python
+
+import (
+	"os/exec"
+)
+
+//go:generate mockgen -destination ../mock_python/command_runner.go . CommandRunner
+type CommandRunner interface {
+	Run(cmd *exec.Cmd) (output string, err error)
+}
+
+type DefaultCommandRunner struct{}
+
+func NewDefaultCommandRunner() *DefaultCommandRunner {
+	return &DefaultCommandRunner{}
+}
+
+func (dcr *DefaultCommandRunner) Run(cmd *exec.Cmd) (output string, err error) {
+	buff, err := cmd.CombinedOutput()
+	return string(buff), err
+}

buildpacks/python/python/function.go

@@ -27,12 +27,12 @@ type Function struct {
 	funcYamlEnvs map[string]string
 }
 
-func NewFunction(opts ...FunctionOpt) Function {
-	f := Function{}
+func NewFunction(opts ...FunctionOpt) *Function {
+	f := &Function{}
 	meta := map[string]string{}
 
 	for _, opt := range opts {
-		opt(&f, meta)
+		opt(f, meta)
 	}
 
 	f.layerContributor = libpak.NewLayerContributor(
@@ -46,7 +46,7 @@ func NewFunction(opts ...FunctionOpt) Function {
 	return f
 }
 
-func (f Function) Contribute(layer libcnb.Layer) (libcnb.Layer, error) {
+func (f *Function) Contribute(layer libcnb.Layer) (libcnb.Layer, error) {
 	f.layerContributor.Logger = f.logger
 
 	return f.layerContributor.Contribute(layer, func() (libcnb.Layer, error) {
@@ -70,7 +70,7 @@ func (f Function) Contribute(layer libcnb.Layer) (libcnb.Layer, error) {
 	})
 }
 
-func (f Function) Name() string {
+func (f *Function) Name() string {
 	return f.layerContributor.Name
 }
 

buildpacks/python/python/invoker.go

@@ -20,12 +20,12 @@ type Invoker struct {
 	pythonPath string
 }
 
-func NewInvoker(dependency libpak.BuildpackDependency, cache libpak.DependencyCache) Invoker {
+func NewInvoker(dependency libpak.BuildpackDependency, cache libpak.DependencyCache) *Invoker {
 	contributor := libpak.NewDependencyLayerContributor(dependency, cache, libcnb.LayerTypes{
 		Launch: true,
 		Cache:  true,
 	})
-	return Invoker{LayerContributor: contributor}
+	return &Invoker{LayerContributor: contributor}
 }
 
 func (i *Invoker) Contribute(layer libcnb.Layer) (libcnb.Layer, error) {

buildpacks/python/python/invoker_dependency_cache.go

@@ -4,7 +4,6 @@
 package python
 
 import (
-	"bytes"
 	"fmt"
 	"os"
 	"os/exec"
@@ -20,16 +19,24 @@ type InvokerDependencyCache struct {
 	LayerContributor libpak.DependencyLayerContributor
 	Logger           bard.Logger
 
-	pythonPath string
+	pythonPath    string
+	commandRunner CommandRunner
 }
 
-func NewInvokerDependencyCache(dependency libpak.BuildpackDependency, cache libpak.DependencyCache) InvokerDependencyCache {
+func NewInvokerDependencyCache(
+	dependency libpak.BuildpackDependency,
+	cache libpak.DependencyCache,
+	commandRunner CommandRunner,
+) *InvokerDependencyCache {
 	contributor := libpak.NewDependencyLayerContributor(dependency, cache, libcnb.LayerTypes{
 		Launch: true,
 		Cache:  true,
 	})
 
-	return InvokerDependencyCache{LayerContributor: contributor}
+	return &InvokerDependencyCache{
+		LayerContributor: contributor,
+		commandRunner:    commandRunner,
+	}
 }
 
 func (i *InvokerDependencyCache) Contribute(layer libcnb.Layer) (libcnb.Layer, error) {
@@ -53,7 +60,7 @@ func (i *InvokerDependencyCache) Contribute(layer libcnb.Layer) (libcnb.Layer, e
 
 		args := []string{
 			"install",
-			"--target=" + i.PythonPath(),
+			"--target", i.PythonPath(),
 			"--no-index",
 			"--find-links", depsDir,
 			"--compile",
@@ -69,12 +76,10 @@ func (i *InvokerDependencyCache) Contribute(layer libcnb.Layer) (libcnb.Layer, e
 
 		args = append(args, files...)
 
-		var stderr bytes.Buffer
 		cmd := exec.Command("pip", args...)
-		cmd.Stderr = &stderr
 
-		if err := cmd.Run(); err != nil {
-			i.Logger.Body("failed to install dependencies: %s", stderr.String())
+		if output, err := i.commandRunner.Run(cmd); err != nil {
+			i.Logger.Body("failed to install dependencies: %s", output)
 			return layer, err
 		}
 

buildpacks/python/python/validation.go

@@ -4,7 +4,6 @@
 package python
 
 import (
-	"bytes"
 	"fmt"
 	"os"
 	"os/exec"
@@ -18,6 +17,7 @@ import (
 type FunctionValidationLayer struct {
 	layerContributor libpak.LayerContributor
 	logger           bard.Logger
+	commandRunner    CommandRunner
 
 	module          string
 	function        string
@@ -31,20 +31,22 @@ type FunctionValidationLayer struct {
 
 type FunctionValidationOpts func(*FunctionValidationLayer, map[string]string)
 
+//go:generate mockgen -destination ../mock_python/layer.go . Layer
 type Layer interface {
 	PythonPath() string
 }
 
-func NewFunctionValidationLayer(appPath string, invoker Layer, InvokerDepLayer Layer, opts ...FunctionValidationOpts) FunctionValidationLayer {
-	fvl := FunctionValidationLayer{
+func NewFunctionValidationLayer(appPath string, invoker Layer, InvokerDepLayer Layer, commandRunner CommandRunner, opts ...FunctionValidationOpts) *FunctionValidationLayer {
+	fvl := &FunctionValidationLayer{
 		applicationPath: appPath,
 		Invoker:         invoker,
 		InvokerDep:      InvokerDepLayer,
+		commandRunner:   commandRunner,
 	}
 	meta := map[string]string{}
 
 	for _, opt := range opts {
-		opt(&fvl, meta)
+		opt(fvl, meta)
 	}
 
 	fvl.layerContributor = libpak.NewLayerContributor("validation", meta, libcnb.LayerTypes{
@@ -54,44 +56,40 @@ func NewFunctionValidationLayer(appPath string, invoker Layer, InvokerDepLayer L
 	return fvl
 }
 
-func (i FunctionValidationLayer) Contribute(layer libcnb.Layer) (libcnb.Layer, error) {
-	i.layerContributor.Logger = i.logger
+func (f *FunctionValidationLayer) Contribute(layer libcnb.Layer) (libcnb.Layer, error) {
+	f.layerContributor.Logger = f.logger
 
-	return i.layerContributor.Contribute(layer, func() (libcnb.Layer, error) {
-		i.logger.Body("Validating function")
+	return f.layerContributor.Contribute(layer, func() (libcnb.Layer, error) {
+		f.logger.Body("Validating function")
 
 		var pythonPath []string
-		if i.Invoker.PythonPath() != "" {
-			pythonPath = append(pythonPath, i.Invoker.PythonPath())
+		if f.Invoker.PythonPath() != "" {
+			pythonPath = append(pythonPath, f.Invoker.PythonPath())
 		}
 
-		if i.InvokerDep.PythonPath() != "" {
-			pythonPath = append(pythonPath, i.InvokerDep.PythonPath())
+		if f.InvokerDep.PythonPath() != "" {
+			pythonPath = append(pythonPath, f.InvokerDep.PythonPath())
 		}
 
 		if env, found := os.LookupEnv("PYTHONPATH"); found {
 			pythonPath = append(pythonPath, env)
 		}
 
-		buffer := bytes.NewBuffer(nil)
-		cmd := exec.Command("python", "-m", "pyfunc", "check", "-s", i.applicationPath)
-		// cmd := exec.Command("env")
+		cmd := exec.Command("python", "-m", "pyfunc", "check", "-s", f.applicationPath)
 		cmd.Env = append(os.Environ(), fmt.Sprintf("PYTHONPATH=%s", strings.Join(pythonPath, string(os.PathListSeparator))))
-		cmd.Env = append(cmd.Env, fmt.Sprintf("%s=%s", EnvModuleName, i.module), fmt.Sprintf("%s=%s", EnvFunctionName, i.function))
-		cmd.Stderr = buffer
-		cmd.Stdout = buffer
+		cmd.Env = append(cmd.Env, fmt.Sprintf("%s=%s", EnvModuleName, f.module), fmt.Sprintf("%s=%s", EnvFunctionName, f.function))
 
-		if err := cmd.Run(); err != nil {
-			return layer, fmt.Errorf("%v: %v", buffer.String(), err)
+		if output, err := f.commandRunner.Run(cmd); err != nil {
+			return layer, fmt.Errorf("%v: %v", output, err)
 		}
 
-		i.logger.Debug("Function was successfully parsed")
+		f.logger.Debug("Function was successfully parsed")
 		return layer, nil
 	})
 }
 
-func (i FunctionValidationLayer) Name() string {
-	return i.layerContributor.Name
+func (f *FunctionValidationLayer) Name() string {
+	return f.layerContributor.Name
 }
 
 func WithValidationLogger(logger bard.Logger) FunctionValidationOpts {