Tidy Up

.gitignore

@@ -1,2 +1,3 @@
 /.bin
 /build
+.idea/

README.md

@@ -2,27 +2,29 @@
 ## `gcr.io/paketo-buildpacks/node-start`
 
 The Paketo Node Start CNB sets the start command for a given node application.
-The buildpack expects that the app contains a valid `server.js` at the root.
+The buildpack will detect when a valid javascript file is present within the 
+application source code directory (see [Application Detection](#application-detection).
 
 ## Integration
 
 This CNB writes a start command, so there's currently no scenario we can
-imagine that you would need to require it as dependency. If a user likes to
-include some other functionality, it can be done independent of the Node Start
-CNB without requiring a dependency of it.
+imagine that you would need to require it as dependency. You may include additional
+functionality in a separate buildpack without requiring anything from this buildpack.
 
 ## Usage
 
 To package this buildpack for consumption:
 
-```
+```shell
 $ ./scripts/package.sh --version <version-number>
 ```
 
-This will create a `buildpackage.cnb` file under the `build` directory which you
-can use to build your app as follows:
-```
-pack build <app-name> -p <path-to-app> -b <path/to/node-engine.cnb> -b build/buildpackage.cnb
+This will create a `build/buildpackage.cnb` file which you can use to build your app as follows:
+```shell
+pack build <app-name> \
+  --path <path-to-app> \
+  --buildpack <path/to/node-engine.cnb> \
+  --buildpack build/buildpackage.cnb
 ```
 
 ## Graceful shutdown and signal handling
@@ -39,11 +41,11 @@ init system that will properly handle signals.
 To specify a project subdirectory to be used as the root of the app, please use
 the `BP_NODE_PROJECT_PATH` environment variable at build time either directly
 (e.g. `pack build my-app --env BP_NODE_PROJECT_PATH=./src/my-app`) or through a
-[`project.toml`
-file](https://github.com/buildpacks/spec/blob/main/extensions/project-descriptor.md).
+[`project.toml` file](https://github.com/buildpacks/spec/blob/main/extensions/project-descriptor.md).
 This could be useful if your app is a part of a monorepo.
 
 ## Application Detection
+
 This buildpack searches your application root for the following files:
 1. `server.js`
 1. `app.js`
@@ -55,30 +57,34 @@ chosen for the start command.
 
 ## BP_LAUNCHPOINT
 
-The BP_LAUNCHPOINT environment variable may be used to specify a file for the
+The `BP_LAUNCHPOINT` environment variable may be used to specify a file for the
 start command that is not included in the above set.
 
 e.g. If `BP_LAUNCHPOINT=./src/launchpoint.js`, the buildpack will verify that
-the file exists and then set the start command using that file `node
-src/launchpoint.js`
+the file exists and then set the start command using that file `node src/launchpoint.js`
 
 ## Enabling reloadable process types
 
 You can configure this buildpack to wrap the entrypoint process of your app
 such that it kills and restarts the process whenever files in the app's working
 directory in the container change. With this feature enabled, copying new
-verisons of source code into the running container will trigger your app's
-process to restart. Set the environment variable `BP_LIVE_RELOAD_ENABLED=true`
-at build time to enable this feature.
+versions of source code into the running container will restart the application process.
+
+Set the environment variable `BP_LIVE_RELOAD_ENABLED=true` at build time to enable this feature.
+
+```shell
+pack build my-app \
+  --env BP_LIVE_RELOAD_ENABLED=true
+````
 
 ## Run Tests
 
 To run all unit tests, run:
-```
+```shell
 ./scripts/unit.sh
 ```
 
 To run all integration tests, run:
-```
+```shell
 /scripts/integration.sh
 ```

build_test.go

@@ -4,7 +4,6 @@ import (
 	"bytes"
 	"errors"
 	"fmt"
-	"os"
 	"testing"
 
 	nodestart "github.com/paketo-buildpacks/node-start"
@@ -27,36 +26,22 @@ func testBuild(t *testing.T, context spec.G, it spec.S) {
 
 		applicationFinder *fakes.ApplicationFinder
 
-		build packit.BuildFunc
+		buildContext packit.BuildContext
+		build        packit.BuildFunc
 	)
 
 	it.Before(func() {
-		var err error
-		layersDir, err = os.MkdirTemp("", "layers")
-		Expect(err).NotTo(HaveOccurred())
-
-		cnbDir, err = os.MkdirTemp("", "cnb")
-		Expect(err).NotTo(HaveOccurred())
-
-		workingDir, err = os.MkdirTemp("", "working-dir")
-		Expect(err).NotTo(HaveOccurred())
+		layersDir = t.TempDir()
+		cnbDir = t.TempDir()
+		workingDir = t.TempDir()
 
 		applicationFinder = &fakes.ApplicationFinder{}
 		applicationFinder.FindCall.Returns.String = "server.js"
 
 		buffer = bytes.NewBuffer(nil)
 		logger := scribe.NewEmitter(buffer)
-		build = nodestart.Build(applicationFinder, logger)
-	})
 
-	it.After(func() {
-		Expect(os.RemoveAll(layersDir)).To(Succeed())
-		Expect(os.RemoveAll(cnbDir)).To(Succeed())
-		Expect(os.RemoveAll(workingDir)).To(Succeed())
-	})
-
-	it("returns a result that provides a node start command", func() {
-		result, err := build(packit.BuildContext{
+		buildContext = packit.BuildContext{
 			WorkingDir: workingDir,
 			CNBPath:    cnbDir,
 			Stack:      "some-stack",
@@ -68,7 +53,12 @@ func testBuild(t *testing.T, context spec.G, it spec.S) {
 				Entries: []packit.BuildpackPlanEntry{},
 			},
 			Layers: packit.Layers{Path: layersDir},
-		})
+		}
+		build = nodestart.Build(applicationFinder, logger)
+	})
+
+	it("returns a result that provides a node start command", func() {
+		result, err := build(buildContext)
 		Expect(err).NotTo(HaveOccurred())
 
 		Expect(result).To(Equal(packit.BuildResult{
@@ -98,27 +88,11 @@ func testBuild(t *testing.T, context spec.G, it spec.S) {
 
 	context("when BP_LIVE_RELOAD_ENABLED=true in the build environment", func() {
 		it.Before(func() {
-			os.Setenv("BP_LIVE_RELOAD_ENABLED", "true")
-		})
-
-		it.After(func() {
-			os.Unsetenv("BP_LIVE_RELOAD_ENABLED")
+			t.Setenv("BP_LIVE_RELOAD_ENABLED", "true")
 		})
 
 		it("adds a reloadable start command and makes it the default", func() {
-			result, err := build(packit.BuildContext{
-				WorkingDir: workingDir,
-				CNBPath:    cnbDir,
-				Stack:      "some-stack",
-				BuildpackInfo: packit.BuildpackInfo{
-					Name:    "Some Buildpack",
-					Version: "some-version",
-				},
-				Plan: packit.BuildpackPlan{
-					Entries: []packit.BuildpackPlanEntry{},
-				},
-				Layers: packit.Layers{Path: layersDir},
-			})
+			result, err := build(buildContext)
 			Expect(err).NotTo(HaveOccurred())
 
 			Expect(result.Launch.Processes).To(Equal([]packit.Process{
@@ -154,48 +128,20 @@ func testBuild(t *testing.T, context spec.G, it spec.S) {
 		context("when the application finding fails", func() {
 			it.Before(func() {
 				applicationFinder.FindCall.Returns.Error = errors.New("failed to find application")
-
 			})
+
 			it("returns an error", func() {
-				_, err := build(packit.BuildContext{
-					WorkingDir: workingDir,
-					CNBPath:    cnbDir,
-					Stack:      "some-stack",
-					BuildpackInfo: packit.BuildpackInfo{
-						Name:    "Some Buildpack",
-						Version: "some-version",
-					},
-					Plan: packit.BuildpackPlan{
-						Entries: []packit.BuildpackPlanEntry{},
-					},
-					Layers: packit.Layers{Path: layersDir},
-				})
+				_, err := build(buildContext)
 				Expect(err).To(MatchError("failed to find application"))
 			})
 		})
 		context("when BP_LIVE_RELOAD_ENABLED is set to an invalid value", func() {
 			it.Before(func() {
-				os.Setenv("BP_LIVE_RELOAD_ENABLED", "not-a-bool")
-			})
-
-			it.After(func() {
-				os.Unsetenv("BP_LIVE_RELOAD_ENABLED")
+				t.Setenv("BP_LIVE_RELOAD_ENABLED", "not-a-bool")
 			})
 
 			it("returns an error", func() {
-				_, err := build(packit.BuildContext{
-					WorkingDir: workingDir,
-					CNBPath:    cnbDir,
-					Stack:      "some-stack",
-					BuildpackInfo: packit.BuildpackInfo{
-						Name:    "Some Buildpack",
-						Version: "some-version",
-					},
-					Plan: packit.BuildpackPlan{
-						Entries: []packit.BuildpackPlanEntry{},
-					},
-					Layers: packit.Layers{Path: layersDir},
-				})
+				_, err := build(buildContext)
 				Expect(err).To(MatchError(ContainSubstring("failed to parse BP_LIVE_RELOAD_ENABLED value not-a-bool")))
 			})
 		})

detect.go

@@ -22,46 +22,22 @@ func Detect(applicationFinder ApplicationFinder) packit.DetectFunc {
 			return packit.DetectResult{}, err
 		}
 
-		requirements := []packit.BuildPlanRequirement{
-			{
-				Name: "node",
-				Metadata: map[string]interface{}{
-					"launch": true,
-				},
-			},
-		}
+		requirements := []packit.BuildPlanRequirement{newLaunchRequirement("node")}
 
-		exists, err := fs.Exists(filepath.Join(context.WorkingDir, os.Getenv("BP_NODE_PROJECT_PATH"), "package.json"))
-		if err != nil {
+		if packageJsonExists, err := fs.Exists(filepath.Join(context.WorkingDir, os.Getenv("BP_NODE_PROJECT_PATH"), "package.json")); err != nil {
 			return packit.DetectResult{}, err
+		} else if packageJsonExists {
+			requirements = append(requirements, newLaunchRequirement("node_modules"))
 		}
 
-		if exists {
-			requirements = append(requirements, packit.BuildPlanRequirement{
-				Name: "node_modules",
-				Metadata: map[string]interface{}{
-					"launch": true,
-				},
-			})
-		}
-
-		shouldReload, err := checkLiveReloadEnabled()
-		if err != nil {
+		if shouldReload, err := checkLiveReloadEnabled(); err != nil {
 			return packit.DetectResult{}, err
-		}
-
-		if shouldReload {
-			requirements = append(requirements, packit.BuildPlanRequirement{
-				Name: "watchexec",
-				Metadata: map[string]interface{}{
-					"launch": true,
-				},
-			})
+		} else if shouldReload {
+			requirements = append(requirements, newLaunchRequirement("watchexec"))
 		}
 
 		return packit.DetectResult{
 			Plan: packit.BuildPlan{
-				Provides: []packit.BuildPlanProvision{},
 				Requires: requirements,
 			},
 		}, nil
@@ -78,3 +54,12 @@ func checkLiveReloadEnabled() (bool, error) {
 	}
 	return false, nil
 }
+
+func newLaunchRequirement(name string) packit.BuildPlanRequirement {
+	return packit.BuildPlanRequirement{
+		Name: name,
+		Metadata: map[string]interface{}{
+			"launch": true,
+		},
+	}
+}

detect_test.go

@@ -25,9 +25,7 @@ func testDetect(t *testing.T, context spec.G, it spec.S) {
 	)
 
 	it.Before(func() {
-		var err error
-		workingDir, err = os.MkdirTemp("", "working-dir")
-		Expect(err).NotTo(HaveOccurred())
+		workingDir = t.TempDir()
 
 		applicationFinder = &fakes.ApplicationFinder{}
 		applicationFinder.FindCall.Returns.String = "./src/server.js"
@@ -37,24 +35,18 @@ func testDetect(t *testing.T, context spec.G, it spec.S) {
 
 	context("when an application is detected in the working dir", func() {
 		it.Before(func() {
-			os.Setenv("BP_NODE_PROJECT_PATH", "./src")
-			os.Setenv("BP_LAUNCHPOINT", "./src/server.js")
+			t.Setenv("BP_NODE_PROJECT_PATH", "./src")
+			t.Setenv("BP_LAUNCHPOINT", "./src/server.js")
 			Expect(os.MkdirAll(filepath.Join(workingDir, "src"), os.ModePerm)).To(Succeed())
 			Expect(os.WriteFile(filepath.Join(workingDir, "src", "server.js"), nil, 0600)).To(Succeed())
 		})
 
-		it.After(func() {
-			os.Unsetenv("BP_NODE_PROJECT_PATH")
-			os.Unsetenv("BP_LAUNCHPOINT")
-		})
-
 		it("detects", func() {
 			result, err := detect(packit.DetectContext{
 				WorkingDir: workingDir,
 			})
 			Expect(err).NotTo(HaveOccurred())
 			Expect(result.Plan).To(Equal(packit.BuildPlan{
-				Provides: []packit.BuildPlanProvision{},
 				Requires: []packit.BuildPlanRequirement{
 					{
 						Name: "node",
@@ -72,11 +64,7 @@ func testDetect(t *testing.T, context spec.G, it spec.S) {
 
 		context("when BP_LIVE_RELOAD_ENABLED=true", func() {
 			it.Before(func() {
-				os.Setenv("BP_LIVE_RELOAD_ENABLED", "true")
-			})
-
-			it.After(func() {
-				os.Unsetenv("BP_LIVE_RELOAD_ENABLED")
+				t.Setenv("BP_LIVE_RELOAD_ENABLED", "true")
 			})
 
 			it("requires watchexec at launch time", func() {
@@ -104,15 +92,11 @@ func testDetect(t *testing.T, context spec.G, it spec.S) {
 
 	context("when a package.json is detected in the working dir", func() {
 		it.Before(func() {
-			os.Setenv("BP_NODE_PROJECT_PATH", "./src")
+			t.Setenv("BP_NODE_PROJECT_PATH", "./src")
 			Expect(os.MkdirAll(filepath.Join(workingDir, "src"), os.ModePerm)).To(Succeed())
 			Expect(os.WriteFile(filepath.Join(workingDir, "src", "package.json"), nil, 0600)).To(Succeed())
 		})
 
-		it.After(func() {
-			os.Unsetenv("BP_NODE_PROJECT_PATH")
-		})
-
 		it("requires node_modules", func() {
 			result, err := detect(packit.DetectContext{
 				WorkingDir: workingDir,
@@ -168,11 +152,7 @@ func testDetect(t *testing.T, context spec.G, it spec.S) {
 
 		context("when BP_LIVE_RELOAD_ENABLED is set to an invalid value", func() {
 			it.Before(func() {
-				os.Setenv("BP_LIVE_RELOAD_ENABLED", "not-a-bool")
-			})
-
-			it.After(func() {
-				os.Unsetenv("BP_LIVE_RELOAD_ENABLED")
+				t.Setenv("BP_LIVE_RELOAD_ENABLED", "not-a-bool")
 			})
 
 			it("returns an error", func() {