Introduce a new step to collate build artifact at the end of the build

The new step collects together all the required build artifacts and
places them in the output directory.

* Reintroduce/add the code removed from step export to preserve the
  legacy export directory structure when skip_export is unset/false
* Add a place holder for a future function that will move just the VHD
  files from the build directory to the output directory when
  skip_export is true
* Add tests for current functionality and placeholder tests for future
  functions

builder/hyperv/common/step_collate_artifacts.go

@@ -0,0 +1,57 @@
+package common
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/hashicorp/packer/helper/multistep"
+	"github.com/hashicorp/packer/packer"
+)
+
+type StepCollateArtifacts struct {
+	OutputDir  string
+	SkipExport bool
+}
+
+// Runs the step required to collate all build artifacts under the
+// specified output directory
+func (s *StepCollateArtifacts) Run(_ context.Context, state multistep.StateBag) multistep.StepAction {
+	driver := state.Get("driver").(Driver)
+	ui := state.Get("ui").(packer.Ui)
+
+	ui.Say("Collating build artifacts...")
+
+	if s.SkipExport {
+		// If the user has chosen to skip a full export of the VM the only
+		// artifacts that they are interested in will be the VHDs
+
+		// TODO: Grab the disks from the build directory and place them in
+		// a folder named 'Virtual Hard Disks' under the output directory
+	} else {
+		// Get the full path to the export directory from the statebag
+		var exportPath string
+		if v, ok := state.GetOk("export_path"); ok {
+			exportPath = v.(string)
+		}
+		// The export process exports the VM into a folder named 'vm name'
+		// under the output directory. However, to maintain backwards
+		// compatibility, we now need to shuffle around the exported folders
+		// so the 'Snapshots', 'Virtual Hard Disks' and 'Virtual Machines'
+		// directories appear *directly* under <output directory>.
+		// The empty '<output directory>/<vm name>' directory is removed
+		// when complete.
+		// The 'Snapshots' folder will not be moved into the output
+		// directory if it is empty.
+		err := driver.PreserveLegacyExportBehaviour(exportPath, s.OutputDir)
+		if err != nil {
+			// No need to halt here; Just warn the user instead
+			err = fmt.Errorf("WARNING: Error restoring legacy export dir structure: %s", err)
+			ui.Error(err.Error())
+		}
+	}
+
+	return multistep.ActionContinue
+}
+
+// Cleanup does nothing
+func (s *StepCollateArtifacts) Cleanup(state multistep.StateBag) {}

builder/hyperv/common/step_collate_artifacts_test.go

@@ -0,0 +1,82 @@
+package common
+
+import (
+	"context"
+	"path/filepath"
+	"testing"
+
+	"github.com/hashicorp/packer/helper/multistep"
+)
+
+func TestStepCollateArtifacts_impl(t *testing.T) {
+	var _ multistep.Step = new(StepCollateArtifacts)
+}
+
+func TestStepCollateArtifacts_exportedArtifacts(t *testing.T) {
+	state := testState(t)
+	step := new(StepCollateArtifacts)
+
+	step.OutputDir = "foopath"
+	vmName := "foo"
+
+	// Uses export path from the state bag
+	exportPath := filepath.Join(step.OutputDir, vmName)
+	state.Put("export_path", exportPath)
+
+	driver := state.Get("driver").(*DriverMock)
+
+	// Test the run
+	if action := step.Run(context.Background(), state); action != multistep.ActionContinue {
+		t.Fatalf("Bad action: %v", action)
+	}
+	if _, ok := state.GetOk("error"); ok {
+		t.Fatal("Should NOT have error")
+	}
+
+	// Test the driver
+	if !driver.PreserveLegacyExportBehaviour_Called {
+		t.Fatal("Should have called PreserveLegacyExportBehaviour")
+	}
+	if driver.PreserveLegacyExportBehaviour_SrcPath != exportPath {
+		t.Fatalf("Should call with correct srcPath. Got: %s Wanted: %s",
+			driver.PreserveLegacyExportBehaviour_SrcPath, exportPath)
+	}
+	if driver.PreserveLegacyExportBehaviour_DstPath != step.OutputDir {
+		t.Fatalf("Should call with correct dstPath. Got: %s Wanted: %s",
+			driver.PreserveLegacyExportBehaviour_DstPath, step.OutputDir)
+	}
+
+	// TODO: Create MoveCreatedVHDsToOutput func etc
+	// if driver.MoveCreatedVHDsToOutput_Called {
+	// t.Fatal("Should NOT have called MoveCreatedVHDsToOutput")
+	// }
+}
+
+func TestStepCollateArtifacts_skipExportedArtifacts(t *testing.T) {
+	state := testState(t)
+	step := new(StepCollateArtifacts)
+
+	// TODO: Needs the path to the main output directory
+	// outputDir := "foopath"
+	// Export has been skipped
+	step.SkipExport = true
+
+	driver := state.Get("driver").(*DriverMock)
+
+	// Test the run
+	if action := step.Run(context.Background(), state); action != multistep.ActionContinue {
+		t.Fatalf("Bad action: %v", action)
+	}
+	if _, ok := state.GetOk("error"); ok {
+		t.Fatal("Should NOT have error")
+	}
+
+	// TODO: Create MoveCreatedVHDsToOutput func etc
+	// if !driver.MoveCreatedVHDsToOutput_Called {
+	// t.Fatal("Should have called MoveCreatedVHDsToOutput")
+	// }
+
+	if driver.PreserveLegacyExportBehaviour_Called {
+		t.Fatal("Should NOT have called PreserveLegacyExportBehaviour")
+	}
+}

builder/hyperv/iso/builder.go

@@ -465,6 +465,10 @@ func (b *Builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) (packe
 			OutputDir:  b.config.OutputDir,
 			SkipExport: b.config.SkipExport,
 		},
+		&hypervcommon.StepCollateArtifacts{
+			OutputDir:  b.config.OutputDir,
+			SkipExport: b.config.SkipExport,
+		},
 
 		// the clean up actions for each step will be executed reverse order
 	}

builder/hyperv/vmcx/builder.go

@@ -482,6 +482,10 @@ func (b *Builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) (packe
 			OutputDir:  b.config.OutputDir,
 			SkipExport: b.config.SkipExport,
 		},
+		&hypervcommon.StepCollateArtifacts{
+			OutputDir:  b.config.OutputDir,
+			SkipExport: b.config.SkipExport,
+		},
 
 		// the clean up actions for each step will be executed reverse order
 	)