create test image with go test -c

docs/reference/ko_apply.md

@@ -66,6 +66,7 @@ ko apply -f FILENAME [flags]
       --tag-only                 Include tags but not digests in resolved image references. Useful when digests are not preserved when images are repopulated.
   -t, --tags strings             Which tags to use for the produced image instead of the default 'latest' tag (may not work properly with --base-import-paths or --bare). (default [latest])
       --tarball string           File to save images tarballs
+      --test                     Use go test -c instead of go build when building Go code.
 ```
 
 ### Options inherited from parent commands

docs/reference/ko_build.md

@@ -60,6 +60,7 @@ ko build IMPORTPATH... [flags]
       --tag-only                 Include tags but not digests in resolved image references. Useful when digests are not preserved when images are repopulated.
   -t, --tags strings             Which tags to use for the produced image instead of the default 'latest' tag (may not work properly with --base-import-paths or --bare). (default [latest])
       --tarball string           File to save images tarballs
+      --test                     Use go test -c instead of go build when building Go code.
 ```
 
 ### Options inherited from parent commands

docs/reference/ko_create.md

@@ -66,6 +66,7 @@ ko create -f FILENAME [flags]
       --tag-only                 Include tags but not digests in resolved image references. Useful when digests are not preserved when images are repopulated.
   -t, --tags strings             Which tags to use for the produced image instead of the default 'latest' tag (may not work properly with --base-import-paths or --bare). (default [latest])
       --tarball string           File to save images tarballs
+      --test                     Use go test -c instead of go build when building Go code.
 ```
 
 ### Options inherited from parent commands

docs/reference/ko_resolve.md

@@ -59,6 +59,7 @@ ko resolve -f FILENAME [flags]
       --tag-only                 Include tags but not digests in resolved image references. Useful when digests are not preserved when images are repopulated.
   -t, --tags strings             Which tags to use for the produced image instead of the default 'latest' tag (may not work properly with --base-import-paths or --bare). (default [latest])
       --tarball string           File to save images tarballs
+      --test                     Use go test -c instead of go build when building Go code.
 ```
 
 ### Options inherited from parent commands

docs/reference/ko_run.md

@@ -48,6 +48,7 @@ ko run IMPORTPATH [flags]
       --tag-only                 Include tags but not digests in resolved image references. Useful when digests are not preserved when images are repopulated.
   -t, --tags strings             Which tags to use for the produced image instead of the default 'latest' tag (may not work properly with --base-import-paths or --bare). (default [latest])
       --tarball string           File to save images tarballs
+      --test                     Use go test -c instead of go build when building Go code.
 ```
 
 ### Options inherited from parent commands

pkg/build/gobuild.go

@@ -86,6 +86,7 @@ type gobuild struct {
 	dir                  string
 	labels               map[string]string
 	semaphore            *semaphore.Weighted
+	createTestBinary     bool
 
 	cache *layerCache
 }
@@ -108,6 +109,7 @@ type gobuildOpener struct {
 	labels               map[string]string
 	dir                  string
 	jobs                 int
+	createTestBinary     bool
 }
 
 func (gbo *gobuildOpener) Open() (Interface, error) {
@@ -134,6 +136,8 @@ func (gbo *gobuildOpener) Open() (Interface, error) {
 		buildConfigs:         gbo.buildConfigs,
 		labels:               gbo.labels,
 		dir:                  gbo.dir,
+		createTestBinary:     gbo.createTestBinary,
+
 		platformMatcher:      matcher,
 		cache: &layerCache{
 			buildToDiff: map[string]buildIDToDiffID{},
@@ -156,12 +160,14 @@ func NewGo(ctx context.Context, dir string, options ...Option) (Interface, error
 		dir:   dir,
 		sbom:  spdx("(none)"),
 	}
-
 	for _, option := range options {
 		if err := option(gbo); err != nil {
 			return nil, err
 		}
 	}
+	if gbo.createTestBinary {
+		gbo.build = buildTest
+	}
 	return gbo.Open()
 }
 
@@ -219,6 +225,9 @@ func (g *gobuild) IsSupportedReference(s string) error {
 	if len(pkgs) != 1 {
 		return fmt.Errorf("found %d local packages, expected 1", len(pkgs))
 	}
+	if g.createTestBinary {
+		return nil
+	}
 	if pkgs[0].Name != "main" {
 		return errors.New("importpath is not `package main`")
 	}
@@ -251,15 +260,26 @@ func getGoBinary() string {
 	}
 	return defaultGoBin
 }
+func buildTest(ctx context.Context, ip string, dir string, platform v1.Platform, config Config) (string, error) {
+	return buildCommon(ctx, ip, dir, platform, config, false)
+}
 
 func build(ctx context.Context, ip string, dir string, platform v1.Platform, config Config) (string, error) {
+	return buildCommon(ctx, ip, dir, platform, config, true)
+}
+
+func buildCommon(ctx context.Context, ip string, dir string, platform v1.Platform, config Config, createTestBinary bool) (string, error) {
 	buildArgs, err := createBuildArgs(config)
 	if err != nil {
 		return "", err
 	}
 
 	args := make([]string, 0, 4+len(buildArgs))
-	args = append(args, "build")
+	if createTestBinary {
+		args = append(args, "test", "-c")
+	} else {
+		args = append(args, "build")
+	}
 	args = append(args, buildArgs...)
 
 	env, err := buildEnv(platform, os.Environ(), config.Env)

pkg/build/gobuilds.go

@@ -32,6 +32,9 @@ type gobuilds struct {
 
 	// workingDirectory is typically ".", but it may be a different value if ko is embedded as a library.
 	workingDirectory string
+
+	// ignore supported reference
+	ignoreSupportedReference bool
 }
 
 // builderWithConfig is not an imaginative name.

pkg/build/options.go

@@ -177,3 +177,11 @@ func WithSBOMDir(dir string) Option {
 		return nil
 	}
 }
+
+// WithCreateTestBinary is a functional option for overriding the go option
+func WithCreateTestBinary(createTestBinary bool) Option {
+	return func(gbo *gobuildOpener) error {
+		gbo.createTestBinary = createTestBinary
+		return nil
+	}
+}

pkg/commands/options/build.go

@@ -69,6 +69,9 @@ type BuildOptions struct {
 
 	// BuildConfigs stores the per-image build config from `.ko.yaml`.
 	BuildConfigs map[string]build.Config
+
+	// compile the test binary
+	CreateTestBinary bool
 }
 
 func AddBuildOptions(cmd *cobra.Command, bo *BuildOptions) {
@@ -84,6 +87,9 @@ func AddBuildOptions(cmd *cobra.Command, bo *BuildOptions) {
 		"Which platform to use when pulling a multi-platform base. Format: all | <os>[/<arch>[/<variant>]][,platform]*")
 	cmd.Flags().StringSliceVar(&bo.Labels, "image-label", []string{},
 		"Which labels (key=value) to add to the image.")
+	cmd.Flags().BoolVar(&bo.CreateTestBinary, "test", bo.CreateTestBinary,
+		"Use go test -c instead of go build when building Go code.")
+
 	bo.Trimpath = true
 }
 

pkg/commands/resolver.go

@@ -126,6 +126,9 @@ func gobuildOptions(bo *options.BuildOptions) ([]build.Option, error) {
 		opts = append(opts, build.WithSBOMDir(bo.SBOMDir))
 	}
 
+	if bo.CreateTestBinary {
+		opts = append(opts, build.WithCreateTestBinary(bo.CreateTestBinary))
+	}
 	return opts, nil
 }