Merge branch 'master' into format-fixes

29 files changed, 709 insertions, 314 deletions

diff --git a/.dockerignore b/.dockerignore
index 402fbc0..52712ed 100644
--- a/.dockerignore
+++ b/.dockerignore
@@ -1,8 +1,10 @@
 /.git
 /.data
+/.cover
 /dist
 /ui
 /utils
 /image
 /cmd
 /build
+coverage.txt
diff --git a/.gitignore b/.gitignore
index 16fccd1..149cdc3 100644
--- a/.gitignore
+++ b/.gitignore
@@ -20,3 +20,4 @@
 *.log
 /dist
 .cover
+coverage.txt
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
new file mode 100644
index 0000000..7ec9505
--- /dev/null
+++ b/.gitlab-ci.yml
@@ -0,0 +1,26 @@
+image: golang:1.12.5
+
+cache:
+  paths:
+    - .cache
+
+variables:
+  GOPATH: $CI_PROJECT_DIR/.cache
+
+stages:
+  - setup
+  - validation
+
+setup:
+  stage: setup
+  script:
+    - mkdir -p .cache
+    - go get ./...
+    - curl -sfL https://install.goreleaser.com/github.com/golangci/golangci-lint.sh | sh -s -- -b $(go env GOPATH)/bin v1.17.1
+
+validation:
+  stage: validation
+  before_script:
+    - export PATH="$GOPATH/bin:$PATH"
+  script:
+    - make ci
diff --git a/.scripts/test.sh b/.scripts/test-coverage.sh
index 36db3a7..36db3a7 100755
--- a/.scripts/test.sh
+++ b/.scripts/test-coverage.sh
diff --git a/.travis.yml b/.travis.yml
deleted file mode 100644
index 38c0be3..0000000
--- a/.travis.yml
+++ /dev/null
@@ -1,34 +0,0 @@
-language: go
-
-os: 
-  - linux
-  - linux-ppc64le
-
-go:
-- '1.9.x'
-- '1.10.x'
-- '1.11.x'
-- 'master'
-
-# Skip the install step. Don't `go get` dependencies. Only build with the
-# code in vendor/
-install: true
-
-matrix:
-  # It's ok if our code fails on unstable development versions of Go.
-  allow_failures:
-  - go: master
-  # Don't wait for tip tests to finish. Mark the test run green if the
-  # tests pass on the stable versions of Go.
-  fast_finish: true
-
-notifications:
-  email: false
-
-before_script:
-- go get -t ./...
-
-# Note: scripts always run to completion
-script:
-- make validate
-- make test
diff --git a/Makefile b/Makefile
index ee0266c..e31f316 100644
--- a/Makefile
+++ b/Makefile
@@ -14,23 +14,26 @@ run-large: build
 build:
 	go build -o build/$(BIN)
 
-release: test validate
+release: test-coverage validate
 	./.scripts/tag.sh
 	goreleaser --rm-dist
 
 install:
 	go install ./...
 
+ci: clean validate test-coverage
+
 test: build
-	go test -cover -v ./...
+	go test -cover -v -race ./...
 
-coverage: build
-	./.scripts/test.sh
+test-coverage: build
+	./.scripts/test-coverage.sh
 
 validate:
 	grep -R 'const allowTestDataCapture = false' ui/
 	go vet ./...
-	@! gofmt -s -d -l . 2>&1 | grep -vE '^\.git/'
+	@! gofmt -s -l . 2>&1 | grep -vE '^\.git/' | grep -vE '^\.cache/'
+	golangci-lint run
 
 lint: build
 	golint -set_exit_status $$(go list ./...)
@@ -40,7 +43,6 @@ generate-test-data:
 
 clean:
 	rm -rf build
-	rm -rf vendor
 	go clean
 
-.PHONY: build install test lint clean release validate generate-test-data
+.PHONY: build install test lint clean release validate generate-test-data test-coverage ci
diff --git a/README.md b/README.md
index 5121130..d13b1b2 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,6 @@
 # dive
 [![Go Report Card](https://goreportcard.com/badge/github.com/wagoodman/dive)](https://goreportcard.com/report/github.com/wagoodman/dive)
-[![Pipeline Status](https://api.travis-ci.org/wagoodman/dive.svg?branch=master)](https://travis-ci.org/wagoodman/dive)
+[![Pipeline Status](https://gitlab.com/wagoodman/dive/badges/master/pipeline.svg)](https://gitlab.com/wagoodman/dive/pipelines?scope=branches&page=1)
 
 **A tool for exploring a docker image, layer contents, and discovering ways to shrink your Docker image size.**
 
@@ -147,7 +147,7 @@ or if you are running with a docker image:
 ```bash
 docker run --rm -it \
     -v /var/run/docker.sock:/var/run/docker.sock \
-    -e DOCKER_API_VERSION=1.37
+    -e DOCKER_API_VERSION=1.37 \
     wagoodman/dive:latest <dive arguments...>
 ```
 
@@ -189,6 +189,8 @@ Key Binding                                | Description
 <kbd>Ctrl + M</kbd>                        | Filetree view: show/hide modified files
 <kbd>Ctrl + U</kbd>                        | Filetree view: show/hide unmodified files
 <kbd>Ctrl + B</kbd>                        | Filetree view: show/hide file attributes
+<kbd>PageUp</kbd>                          | Filetree view: scroll up a page
+<kbd>PageDown</kbd>                        | Filetree view: scroll down a page
 
 ## UI Configuration
 
diff --git a/cmd/analyze.go b/cmd/analyze.go
index eab81f2..937378a 100644
--- a/cmd/analyze.go
+++ b/cmd/analyze.go
@@ -20,14 +20,14 @@ func doAnalyzeCmd(cmd *cobra.Command, args []string) {
 		}
 
 		fmt.Println("No image argument given")
-		cmd.Help()
+		_ = cmd.Help()
 		utils.Exit(1)
 	}
 
 	userImage := args[0]
 	if userImage == "" {
 		fmt.Println("No image argument given")
-		cmd.Help()
+		_ = cmd.Help()
 		utils.Exit(1)
 	}
 
diff --git a/cmd/root.go b/cmd/root.go
index ec2dc0a..e360cbf 100644
--- a/cmd/root.go
+++ b/cmd/root.go
@@ -70,7 +70,7 @@ func initConfig() {
 	viper.SetDefault("keybinding.toggle-added-files", "ctrl+a")
 	viper.SetDefault("keybinding.toggle-removed-files", "ctrl+r")
 	viper.SetDefault("keybinding.toggle-modified-files", "ctrl+m")
-	viper.SetDefault("keybinding.toggle-unchanged-files", "ctrl+u")
+	viper.SetDefault("keybinding.toggle-unmodified-files", "ctrl+u")
 	viper.SetDefault("keybinding.page-up", "pgup")
 	viper.SetDefault("keybinding.page-down", "pgdn")
 
diff --git a/filetree/cache.go b/filetree/cache.go
index 3dde39a..6e676c3 100644
--- a/filetree/cache.go
+++ b/filetree/cache.go
@@ -17,8 +17,6 @@ func (cache *TreeCache) Get(bottomTreeStart, bottomTreeStop, topTreeStart, topTr
 	key := TreeCacheKey{bottomTreeStart, bottomTreeStop, topTreeStart, topTreeStop}
 	if value, exists := cache.cache[key]; exists {
 		return value
-	} else {
-
 	}
 	value := cache.buildTree(key)
 	cache.cache[key] = value
diff --git a/filetree/data.go b/filetree/data.go
index 64ceceb..743ecb0 100644
--- a/filetree/data.go
+++ b/filetree/data.go
@@ -10,8 +10,8 @@ import (
 )
 
 const (
-	Unchanged DiffType = iota
-	Changed
+	Unmodified DiffType = iota
+	Modified
 	Added
 	Removed
 )
@@ -23,7 +23,7 @@ func NewNodeData() *NodeData {
 	return &NodeData{
 		ViewInfo: *NewViewInfo(),
 		FileInfo: FileInfo{},
-		DiffType: Unchanged,
+		DiffType: Unmodified,
 	}
 }
 
@@ -64,7 +64,10 @@ func getHashFromReader(reader io.Reader) uint64 {
 			break
 		}
 
-		h.Write(buf[:n])
+		_, err = h.Write(buf[:n])
+		if err != nil {
+			logrus.Panic(err)
+		}
 	}
 
 	return h.Sum64()
@@ -126,19 +129,19 @@ func (data *FileInfo) Compare(other FileInfo) DiffType {
 			data.Mode == other.Mode &&
 			data.Uid == other.Uid &&
 			data.Gid == other.Gid {
-			return Unchanged
+			return Unmodified
 		}
 	}
-	return Changed
+	return Modified
 }
 
 // String of a DiffType
 func (diff DiffType) String() string {
 	switch diff {
-	case Unchanged:
-		return "Unchanged"
-	case Changed:
-		return "Changed"
+	case Unmodified:
+		return "Unmodified"
+	case Modified:
+		return "Modified"
 	case Added:
 		return "Added"
 	case Removed:
@@ -154,5 +157,5 @@ func (diff DiffType) merge(other DiffType) DiffType {
 	if diff == other {
 		return diff
 	}
-	return Changed
+	return Modified
 }
diff --git a/filetree/data_test.go b/filetree/data_test.go
index 7c9fad7..351d6df 100644
--- a/filetree/data_test.go
+++ b/filetree/data_test.go
@@ -10,23 +10,23 @@ func TestAssignDiffType(t *testing.T) {
 	if err != nil {
 		t.Errorf("Expected no error from fetching path. got: %v", err)
 	}
-	node.Data.DiffType = Changed
-	if tree.Root.Children["usr"].Data.DiffType != Changed {
+	node.Data.DiffType = Modified
+	if tree.Root.Children["usr"].Data.DiffType != Modified {
 		t.Fail()
 	}
 }
 
 func TestMergeDiffTypes(t *testing.T) {
-	a := Unchanged
-	b := Unchanged
+	a := Unmodified
+	b := Unmodified
 	merged := a.merge(b)
-	if merged != Unchanged {
+	if merged != Unmodified {
 		t.Errorf("Expected Unchaged (0) but got %v", merged)
 	}
-	a = Changed
-	b = Unchanged
+	a = Modified
+	b = Unmodified
 	merged = a.merge(b)
-	if merged != Changed {
+	if merged != Modified {
 		t.Errorf("Expected Unchaged (0) but got %v", merged)
 	}
 }
diff --git a/filetree/efficiency_test.go b/filetree/efficiency_test.go
index e461201..831ceb5 100644
--- a/filetree/efficiency_test.go
+++ b/filetree/efficiency_test.go
@@ -4,19 +4,31 @@ import (
 	"testing"
 )
 
+func checkError(t *testing.T, err error, message string) {
+	if err != nil {
+		t.Errorf(message+": %+v", err)
+	}
+}
+
 func TestEfficency(t *testing.T) {
 	trees := make([]*FileTree, 3)
 	for idx := range trees {
 		trees[idx] = NewFileTree()
 	}
 
-	trees[0].AddPath("/etc/nginx/nginx.conf", FileInfo{Size: 2000})
-	trees[0].AddPath("/etc/nginx/public", FileInfo{Size: 3000})
+	_, _, err := trees[0].AddPath("/etc/nginx/nginx.conf", FileInfo{Size: 2000})
+	checkError(t, err, "could not setup test")
+
+	_, _, err = trees[0].AddPath("/etc/nginx/public", FileInfo{Size: 3000})
+	checkError(t, err, "could not setup test")
 
-	trees[1].AddPath("/etc/nginx/nginx.conf", FileInfo{Size: 5000})
-	trees[1].AddPath("/etc/athing", FileInfo{Size: 10000})
+	_, _, err = trees[1].AddPath("/etc/nginx/nginx.conf", FileInfo{Size: 5000})
+	checkError(t, err, "could not setup test")
+	_, _, err = trees[1].AddPath("/etc/athing", FileInfo{Size: 10000})
+	checkError(t, err, "could not setup test")
 
-	trees[2].AddPath("/etc/.wh.nginx", *BlankFileChangeInfo("/etc/.wh.nginx"))
+	_, _, err = trees[2].AddPath("/etc/.wh.nginx", *BlankFileChangeInfo("/etc/.wh.nginx"))
+	checkError(t, err, "could not setup test")
 
 	var expectedScore = 0.75
 	var expectedMatches = EfficiencySlice{
@@ -50,7 +62,8 @@ func TestEfficency_ScratchImage(t *testing.T) {
 		trees[idx] = NewFileTree()
 	}
 
-	trees[0].AddPath("/nothing", FileInfo{Size: 0})
+	_, _, err := trees[0].AddPath("/nothing", FileInfo{Size: 0})
+	checkError(t, err, "could not setup test")
 
 	var expectedScore = 1.0
 	var expectedMatches = EfficiencySlice{}
diff --git a/filetree/node.go b/filetree/node.go
index 48fa6e4..d136f0d 100644
--- a/filetree/node.go
+++ b/filetree/node.go
@@ -18,10 +18,10 @@ const (
 )
 
 var diffTypeColor = map[DiffType]*color.Color{
-	Added:     color.New(color.FgGreen),
-	Removed:   color.New(color.FgRed),
-	Changed:   color.New(color.FgYellow),
-	Unchanged: color.New(color.Reset),
+	Added:      color.New(color.FgGreen),
+	Removed:    color.New(color.FgRed),
+	Modified:   color.New(color.FgYellow),
+	Unmodified: color.New(color.Reset),
 }
 
 // NewNode creates a new FileNode relative to the given parent node with a payload.
@@ -101,7 +101,10 @@ func (node *FileNode) Remove() error {
 		return fmt.Errorf("cannot remove the tree root")
 	}
 	for _, child := range node.Children {
-		child.Remove()
+		err := child.Remove()
+		if err != nil {
+			return err
+		}
 	}
 	delete(node.Parent.Children, node.Name)
 	node.Tree.Size--
@@ -290,7 +293,7 @@ func (node *FileNode) AssignDiffType(diffType DiffType) error {
 // compare the current node against the given node, returning a definitive DiffType.
 func (node *FileNode) compare(other *FileNode) DiffType {
 	if node == nil && other == nil {
-		return Unchanged
+		return Unmodified
 	}
 
 	if node == nil && other != nil {
diff --git a/filetree/node_test.go b/filetree/node_test.go
index a902e48..a344475 100644
--- a/filetree/node_test.go
+++ b/filetree/node_test.go
@@ -56,7 +56,8 @@ func TestRemoveChild(t *testing.T) {
 	forth := two.AddChild("forth", FileInfo{})
 	two.AddChild("fifth", FileInfo{})
 
-	forth.Remove()
+	err := forth.Remove()
+	checkError(t, err, "unable to setup test")
 
 	expected, actual = 4, tree.Size
 	if expected != actual {
@@ -67,7 +68,8 @@ func TestRemoveChild(t *testing.T) {
 		t.Errorf("Expected 'forth' node to be deleted.")
 	}
 
-	two.Remove()
+	err = two.Remove()
+	checkError(t, err, "unable to setup test")
 
 	expected, actual = 2, tree.Size
 	if expected != actual {
@@ -113,7 +115,7 @@ func TestIsWhiteout(t *testing.T) {
 func TestDiffTypeFromAddedChildren(t *testing.T) {
 	tree := NewFileTree()
 	node, _, _ := tree.AddPath("/usr", *BlankFileChangeInfo("/usr"))
-	node.Data.DiffType = Unchanged
+	node.Data.DiffType = Unmodified
 
 	node, _, _ = tree.AddPath("/usr/bin", *BlankFileChangeInfo("/usr/bin"))
 	node.Data.DiffType = Added
@@ -121,37 +123,42 @@ func TestDiffTypeFromAddedChildren(t *testing.T) {
 	node, _, _ = tree.AddPath("/usr/bin2", *BlankFileChangeInfo("/usr/bin2"))
 	node.Data.DiffType = Removed
 
-	tree.Root.Children["usr"].deriveDiffType(Unchanged)
+	err := tree.Root.Children["usr"].deriveDiffType(Unmodified)
+	checkError(t, err, "unable to setup test")
 
-	if tree.Root.Children["usr"].Data.DiffType != Changed {
-		t.Errorf("Expected Changed but got %v", tree.Root.Children["usr"].Data.DiffType)
+	if tree.Root.Children["usr"].Data.DiffType != Modified {
+		t.Errorf("Expected Modified but got %v", tree.Root.Children["usr"].Data.DiffType)
 	}
 }
 func TestDiffTypeFromRemovedChildren(t *testing.T) {
 	tree := NewFileTree()
-	node, _, _ := tree.AddPath("/usr", *BlankFileChangeInfo("/usr"))
+	_, _, _ = tree.AddPath("/usr", *BlankFileChangeInfo("/usr"))
 
 	info1 := BlankFileChangeInfo("/usr/.wh.bin")
-	node, _, _ = tree.AddPath("/usr/.wh.bin", *info1)
+	node, _, _ := tree.AddPath("/usr/.wh.bin", *info1)
 	node.Data.DiffType = Removed
 
 	info2 := BlankFileChangeInfo("/usr/.wh.bin2")
 	node, _, _ = tree.AddPath("/usr/.wh.bin2", *info2)
 	node.Data.DiffType = Removed
 
-	tree.Root.Children["usr"].deriveDiffType(Unchanged)
+	err := tree.Root.Children["usr"].deriveDiffType(Unmodified)
+	checkError(t, err, "unable to setup test")
 
-	if tree.Root.Children["usr"].Data.DiffType != Changed {
-		t.Errorf("Expected Changed but got %v", tree.Root.Children["usr"].Data.DiffType)
+	if tree.Root.Children["usr"].Data.DiffType != Modified {
+		t.Errorf("Expected Modified but got %v", tree.Root.Children["usr"].Data.DiffType)
 	}
 
 }
 
 func TestDirSize(t *testing.T) {
 	tree1 := NewFileTree()
-	tree1.AddPath("/etc/nginx/public1", FileInfo{Size: 100})
-	tree1.AddPath("/etc/nginx/thing1", FileInfo{Size: 200})
-	tree1.AddPath("/etc/nginx/public3/thing2", FileInfo{Size: 300})
+	_, _, err := tree1.AddPath("/etc/nginx/public1", FileInfo{Size: 100})
+	checkError(t, err, "unable to setup test")
+	_, _, err = tree1.AddPath("/etc/nginx/thing1", FileInfo{Size: 200})
+	checkError(t, err, "unable to setup test")
+	_, _, err = tree1.AddPath("/etc/nginx/public3/thing2", FileInfo{Size: 300})
+	checkError(t, err, "unable to setup test")
 
 	node, _ := tree1.GetNode("/etc/nginx")
 	expected, actual := "----------         0:0      600 B ", node.MetadataString()
diff --git a/filetree/tree.go b/filetree/tree.go
index b225224..192ad8d 100644
--- a/filetree/tree.go
+++ b/filetree/tree.go
@@ -242,6 +242,11 @@ func (tree *FileTree) AddPath(path string, data FileInfo) (*FileNode, []*FileNod
 		if node.Children[name] != nil {
 			node = node.Children[name]
 		} else {
+			// don't add paths that should be deleted
+			if strings.HasPrefix(name, doubleWhiteoutPrefix) {
+				return nil, addedNodes, nil
+			}
+
 			// don't attach the payload. The payload is destined for the
 			// Path's end node, not any intermediary node.
 			node = node.AddChild(name, FileInfo{})
@@ -249,7 +254,7 @@ func (tree *FileTree) AddPath(path string, data FileInfo) (*FileNode, []*FileNod
 
 			if node == nil {
 				// the child could not be added
-				return node, addedNodes, fmt.Errorf(fmt.Sprintf("could not add child node '%s'", name))
+				return node, addedNodes, fmt.Errorf(fmt.Sprintf("could not add child node: '%s' (path:'%s')", name, path))
 			}
 		}
 
@@ -326,9 +331,15 @@ func (tree *FileTree) CompareAndMark(upper *FileTree) error {
 	// take note of the comparison results on each note in the owning tree.
 	for _, pair := range modifications {
 		if pair.final > 0 {
-			pair.lowerNode.AssignDiffType(pair.final)
-		} else if pair.lowerNode.Data.DiffType == Unchanged {
-			pair.lowerNode.deriveDiffType(pair.tentative)
+			err = pair.lowerNode.AssignDiffType(pair.final)
+			if err != nil {
+				return err
+			}
+		} else if pair.lowerNode.Data.DiffType == Unmodified {
+			err = pair.lowerNode.deriveDiffType(pair.tentative)
+			if err != nil {
+				return err
+			}
 		}
 
 		// persist the upper's payload on the owning tree
diff --git a/filetree/tree_test.go b/filetree/tree_test.go
index b1a2c6b..fc57036 100644
--- a/filetree/tree_test.go
+++ b/filetree/tree_test.go
@@ -87,12 +87,30 @@ func TestString(t *testing.T) {
 
 func TestStringBetween(t *testing.T) {
 	tree := NewFileTree()
-	tree.AddPath("/etc/nginx/nginx.conf", FileInfo{})
-	tree.AddPath("/etc/nginx/public", FileInfo{})
-	tree.AddPath("/var/run/systemd", FileInfo{})
-	tree.AddPath("/var/run/bashful", FileInfo{})
-	tree.AddPath("/tmp", FileInfo{})
-	tree.AddPath("/tmp/nonsense", FileInfo{})
+	_, _, err := tree.AddPath("/etc/nginx/nginx.conf", FileInfo{})
+	if err != nil {
+		t.Errorf("could not setup test: %v", err)
+	}
+	_, _, err = tree.AddPath("/etc/nginx/public", FileInfo{})
+	if err != nil {
+		t.Errorf("could not setup test: %v", err)
+	}
+	_, _, err = tree.AddPath("/var/run/systemd", FileInfo{})
+	if err != nil {
+		t.Errorf("could not setup test: %v", err)
+	}
+	_, _, err = tree.AddPath("/var/run/bashful", FileInfo{})
+	if err != nil {
+		t.Errorf("could not setup test: %v", err)
+	}
+	_, _, err = tree.AddPath("/tmp", FileInfo{})
+	if err != nil {
+		t.Errorf("could not setup test: %v", err)
+	}
+	_, _, err = tree.AddPath("/tmp/nonsense", FileInfo{})
+	if err != nil {
+		t.Errorf("could not setup test: %v", err)
+	}
 
 	expected :=
 		`│       └── public
@@ -109,12 +127,30 @@ func TestStringBetween(t *testing.T) {
 
 func TestAddPath(t *testing.T) {
 	tree := NewFileTree()
-	tree.AddPath("/etc/nginx/nginx.conf", FileInfo{})
-	tree.AddPath("/etc/nginx/public", FileInfo{})
-	tree.AddPath("/var/run/systemd", FileInfo{})
-	tree.AddPath("/var/run/bashful", FileInfo{})
-	tree.AddPath("/tmp", FileInfo{})
-	tree.AddPath("/tmp/nonsense", FileInfo{})
+	_, _, err := tree.AddPath("/etc/nginx/nginx.conf", FileInfo{})
+	if err != nil {
+		t.Errorf("could not setup test: %v", err)
+	}
+	_, _, err = tree.AddPath("/etc/nginx/public", FileInfo{})
+	if err != nil {
+		t.Errorf("could not setup test: %v", err)
+	}
+	_, _, err = tree.AddPath("/var/run/systemd", FileInfo{})
+	if err != nil {
+		t.Errorf("could not setup test: %v", err)
+	}
+	_, _, err = tree.AddPath("/var/run/bashful", FileInfo{})
+	if err != nil {
+		t.Errorf("could not setup test: %v", err)
+	}
+	_, _, err = tree.AddPath("/tmp", FileInfo{})
+	if err != nil {
+		t.Errorf("could not setup test: %v", err)
+	}
+	_, _, err = tree.AddPath("/tmp/nonsense", FileInfo{})
+	if err != nil {
+		t.Errorf("could not setup test: %v", err)
+	}
 
 	expected :=
 		`├── etc
@@ -136,17 +172,65 @@ func TestAddPath(t *testing.T) {
 
 }
 
+func TestAddWhiteoutPath(t *testing.T) {
+	tree := NewFileTree()
+	node, _, err := tree.AddPath("usr/local/lib/python3.7/site-packages/pip/.wh..wh..opq", FileInfo{})
+	if err != nil {
+		t.Errorf("expected no error but got: %v", err)
+	}
+	if node != nil {
+		t.Errorf("expected node to be nil, but got: %v", node)
+	}
+	expected :=
+		`└── usr
+    └── local
+        └── lib
+            └── python3.7
+                └── site-packages
+                    └── pip
+`
+	actual := tree.String(false)
+
+	if expected != actual {
+		t.Errorf("Expected tree string:\n--->%s<---\nGot:\n--->%s<---", expected, actual)
+	}
+}
+
 func TestRemovePath(t *testing.T) {
 	tree := NewFileTree()
-	tree.AddPath("/etc/nginx/nginx.conf", FileInfo{})
-	tree.AddPath("/etc/nginx/public", FileInfo{})
-	tree.AddPath("/var/run/systemd", FileInfo{})
-	tree.AddPath("/var/run/bashful", FileInfo{})
-	tree.AddPath("/tmp", FileInfo{})
-	tree.AddPath("/tmp/nonsense", FileInfo{})
+	_, _, err := tree.AddPath("/etc/nginx/nginx.conf", FileInfo{})
+	if err != nil {
+		t.Errorf("could not setup test: %v", err)
+	}
+	_, _, err = tree.AddPath("/etc/nginx/public", FileInfo{})
+	if err != nil {
+		t.Errorf("could not setup test: %v", err)
+	}
+	_, _, err = tree.AddPath("/var/run/systemd", FileInfo{})
+	if err != nil {
+		t.Errorf("could not setup test: %v", err)
+	}
+	_, _, err = tree.AddPath("/var/run/bashful", FileInfo{})
+	if err != nil {
+		t.Errorf("could not setup test: %v", err)
+	}
+	_, _, err = tree.AddPath("/tmp", FileInfo{})
+	if err != nil {
+		t.Errorf("could not setup test: %v", err)
+	}
+	_, _, err = tree.AddPath("/tmp/nonsense", FileInfo{})
+	if err != nil {
+		t.Errorf("could not setup test: %v", err)
+	}
 
-	tree.RemovePath("/var/run/bashful")
-	tree.RemovePath("/tmp")
+	err = tree.RemovePath("/var/run/bashful")
+	if err != nil {
+		t.Errorf("could not setup test: %v", err)
+	}
+	err = tree.RemovePath("/tmp")
+	if err != nil {
+		t.Errorf("could not setup test: %v", err)
+	}
 
 	expected :=
 		`├── etc
@@ -173,24 +257,57 @@ func TestStack(t *testing.T) {
 
 	tree1 := NewFileTree()
 
-	tree1.AddPath("/etc/nginx/public", FileInfo{})
-	tree1.AddPath(payloadKey, FileInfo{})
-	tree1.AddPath("/var/run/bashful", FileInfo{})
-	tree1.AddPath("/tmp", FileInfo{})
-	tree1.AddPath("/tmp/nonsense", FileInfo{})
+	_, _, err := tree1.AddPath("/etc/nginx/public", FileInfo{})
+	if err != nil {
+		t.Errorf("could not setup test: %v", err)
+	}
+	_, _, err = tree1.AddPath(payloadKey, FileInfo{})
+	if err != nil {
+		t.Errorf("could not setup test: %v", err)
+	}
+	_, _, err = tree1.AddPath("/var/run/bashful", FileInfo{})
+	if err != nil {
+		t.Errorf("could not setup test: %v", err)
+	}
+	_, _, err = tree1.AddPath("/tmp", FileInfo{})
+	if err != nil {
+		t.Errorf("could not setup test: %v", err)
+	}
+	_, _, err = tree1.AddPath("/tmp/nonsense", FileInfo{})
+	if err != nil {
+		t.Errorf("could not setup test: %v", err)
+	}
 
 	tree2 := NewFileTree()
 	// add new files
-	tree2.AddPath("/etc/nginx/nginx.conf", FileInfo{})
+	_, _, err = tree2.AddPath("/etc/nginx/nginx.conf", FileInfo{})
+	if err != nil {
+		t.Errorf("could not setup test: %v", err)
+	}
 	// modify current files
-	tree2.AddPath(payloadKey, payloadValue)
+	_, _, err = tree2.AddPath(payloadKey, payloadValue)
+	if err != nil {
+		t.Errorf("could not setup test: %v", err)
+	}
 	// whiteout the following files
-	tree2.AddPath("/var/run/.wh.bashful", FileInfo{})
-	tree2.AddPath("/.wh.tmp", FileInfo{})
+	_, _, err = tree2.AddPath("/var/run/.wh.bashful", FileInfo{})
+	if err != nil {
+		t.Errorf("could not setup test: %v", err)
+	}
+	_, _, err = tree2.AddPath("/.wh.tmp", FileInfo{})
+	if err != nil {
+		t.Errorf("could not setup test: %v", err)
+	}
 	// ignore opaque whiteout files entirely
-	tree2.AddPath("/.wh..wh..opq", FileInfo{})
+	node, _, err := tree2.AddPath("/.wh..wh..opq", FileInfo{})
+	if err != nil {
+		t.Errorf("expected no error on whiteout file add, but got %v", err)
+	}
+	if node != nil {
+		t.Errorf("expected no node on whiteout file add, but got %v", node)
+	}
 
-	err := tree1.Stack(tree2)
+	err = tree1.Stack(tree2)
 
 	if err != nil {
 		t.Errorf("Could not stack refTrees: %v", err)
@@ -206,12 +323,12 @@ func TestStack(t *testing.T) {
         └── systemd
 `
 
-	node, err := tree1.GetNode(payloadKey)
+	node, err = tree1.GetNode(payloadKey)
 	if err != nil {