diff --git a/dive/filetree/comparer_test.go b/dive/filetree/comparer_test.go
index 9e7209c..59f3095 100644
--- a/dive/filetree/comparer_test.go
+++ b/dive/filetree/comparer_test.go
@@ -331,3 +331,267 @@ func TestEfficiencySlice_Less(t *testing.T) {
 		assert.False(t, efs.Less(0, 1))
 	})
 }
+
+func TestComparer_GetPathErrors_Additional(t *testing.T) {
+	t.Run("get path errors with actual errors", func(t *testing.T) {
+		// Create ref trees with some content that will generate path errors
+		tree1 := NewFileTree()
+		tree1.Name = "tree1"
+
+		// Add some paths to tree1
+		fakeData := FileInfo{
+			Path:     "/file1.txt",
+			TypeFlag: 1,
+			hash:     123,
+		}
+		tree1.AddPath("/file1.txt", fakeData)
+
+		tree2 := NewFileTree()
+		tree2.Name = "tree2"
+
+		cmp := NewComparer([]*FileTree{tree1, tree2})
+
+		// Test getting path errors for a key
+		key := NewTreeIndexKey(0, 0, 1, 1)
+
+		pathErrors, err := cmp.GetPathErrors(key)
+
+		// Should not error
+		assert.NoError(t, err)
+		assert.NotNil(t, pathErrors)
+	})
+
+	t.Run("get path errors caches result", func(t *testing.T) {
+		tree1 := NewFileTree()
+		tree1.Name = "tree1"
+
+		fakeData := FileInfo{
+			Path:     "/file1.txt",
+			TypeFlag: 1,
+			hash:     123,
+		}
+		tree1.AddPath("/file1.txt", fakeData)
+
+		cmp := NewComparer([]*FileTree{tree1})
+
+		key := NewTreeIndexKey(0, 0, 0, 0)
+
+		// Call GetPathErrors twice
+		pathErrors1, err1 := cmp.GetPathErrors(key)
+		pathErrors2, err2 := cmp.GetPathErrors(key)
+
+		assert.NoError(t, err1)
+		assert.NoError(t, err2)
+		assert.Equal(t, pathErrors1, pathErrors2)
+	})
+}
+
+func TestComparer_get_ErrorCases(t *testing.T) {
+	t.Run("get returns error on invalid range", func(t *testing.T) {
+		tree1 := NewFileTree()
+		tree1.Name = "tree1"
+
+		cmp := NewComparer([]*FileTree{tree1})
+
+		// Use invalid range (index out of bounds)
+		key := NewTreeIndexKey(0, 10, 0, 0)
+
+		// StackTreeRange will panic with index out of range
+		assert.Panics(t, func() {
+			cmp.get(key)
+		}, "Expected panic when using invalid range")
+	})
+}
+
+func TestComparer_BuildCache_ErrorCases(t *testing.T) {
+	t.Run("build cache with single tree and errors", func(t *testing.T) {
+		tree1 := NewFileTree()
+		tree1.Name = "tree1"
+
+		// Add a path that might cause issues
+		fakeData := FileInfo{
+			Path:     "/file1.txt",
+			TypeFlag: 1,
+			hash:     123,
+		}
+		_, _, err := tree1.AddPath("/file1.txt", fakeData)
+		assert.NoError(t, err)
+
+		cmp := NewComparer([]*FileTree{tree1})
+
+		errors := cmp.BuildCache()
+
+		// Should not error with valid tree
+		assert.Empty(t, errors)
+	})
+
+	t.Run("build cache with multiple trees", func(t *testing.T) {
+		trees := make([]*FileTree, 3)
+		for i := 0; i < 3; i++ {
+			trees[i] = NewFileTree()
+			trees[i].Name = fmt.Sprintf("tree%d", i)
+
+			// Add some content
+			fakeData := FileInfo{
+				Path:     fmt.Sprintf("/file%d.txt", i),
+				TypeFlag: 1,
+				hash:     uint64(i),
+			}
+			_, _, err := trees[i].AddPath(fakeData.Path, fakeData)
+			assert.NoError(t, err)
+		}
+
+		cmp := NewComparer(trees)
+
+		errors := cmp.BuildCache()
+
+		// Should not error
+		assert.Empty(t, errors)
+	})
+
+	t.Run("build cache with empty ref trees", func(t *testing.T) {
+		cmp := NewComparer([]*FileTree{})
+
+		errors := cmp.BuildCache()
+
+		// Should not error even with empty trees
+		assert.Empty(t, errors)
+	})
+}
+
+func TestComparer_GetTree_Caching(t *testing.T) {
+	t.Run("cached tree returns same instance", func(t *testing.T) {
+		tree1 := NewFileTree()
+		tree1.Name = "tree1"
+
+		fakeData := FileInfo{
+			Path:     "/file1.txt",
+			TypeFlag: 1,
+			hash:     123,
+		}
+		_, _, err := tree1.AddPath("/file1.txt", fakeData)
+		assert.NoError(t, err)
+
+		cmp := NewComparer([]*FileTree{tree1})
+
+		key := NewTreeIndexKey(0, 0, 0, 0)
+
+		// Call GetTree twice
+		tree1, err1 := cmp.GetTree(key)
+		tree2, err2 := cmp.GetTree(key)
+
+		assert.NoError(t, err1)
+		assert.NoError(t, err2)
+		assert.NotNil(t, tree1)
+		assert.NotNil(t, tree2)
+		// Should return the same cached instance
+		assert.Same(t, tree1, tree2)
+	})
+
+	t.Run("get tree populates cache", func(t *testing.T) {
+		tree1 := NewFileTree()
+		tree1.Name = "tree1"
+
+		fakeData := FileInfo{
+			Path:     "/file1.txt",
+			TypeFlag: 1,
+			hash:     123,
+		}
+		_, _, err := tree1.AddPath("/file1.txt", fakeData)
+		assert.NoError(t, err)
+
+		cmp := NewComparer([]*FileTree{tree1})
+
+		key := NewTreeIndexKey(0, 0, 0, 0)
+
+		// Cache should be empty initially
+		_, exists := cmp.trees[key]
+		assert.False(t, exists)
+
+		// Get tree should populate cache
+		_, err = cmp.GetTree(key)
+		assert.NoError(t, err)
+
+		// Cache should now have the tree
+		_, exists = cmp.trees[key]
+		assert.True(t, exists)
+	})
+}
+
+func TestComparer_Indexes_Iteration(t *testing.T) {
+	t.Run("natural indexes iteration", func(t *testing.T) {
+		trees := make([]*FileTree, 3)
+		for i := 0; i < 3; i++ {
+			trees[i] = NewFileTree()
+			trees[i].Name = fmt.Sprintf("tree%d", i)
+		}
+
+		cmp := NewComparer(trees)
+
+		// Collect all indexes
+		indexes := make([]TreeIndexKey, 0)
+		for index := range cmp.NaturalIndexes() {
+			indexes = append(indexes, index)
+		}
+
+		// Should have 3 indexes (one for each tree)
+		assert.Len(t, indexes, 3)
+
+		// Verify the indexes
+		assert.Equal(t, NewTreeIndexKey(0, 0, 0, 0), indexes[0])
+		assert.Equal(t, NewTreeIndexKey(0, 0, 1, 1), indexes[1])
+		assert.Equal(t, NewTreeIndexKey(0, 1, 2, 2), indexes[2])
+	})
+
+	t.Run("aggregated indexes iteration", func(t *testing.T) {
+		trees := make([]*FileTree, 3)
+		for i := 0; i < 3; i++ {
+			trees[i] = NewFileTree()
+			trees[i].Name = fmt.Sprintf("tree%d", i)
+		}
+
+		cmp := NewComparer(trees)
+
+		// Collect all indexes
+		indexes := make([]TreeIndexKey, 0)
+		for index := range cmp.AggregatedIndexes() {
+			indexes = append(indexes, index)
+		}
+
+		// Should have 3 indexes
+		assert.Len(t, indexes, 3)
+
+		// Verify the indexes
+		assert.Equal(t, NewTreeIndexKey(0, 0, 0, 0), indexes[0])
+		assert.Equal(t, NewTreeIndexKey(0, 0, 1, 1), indexes[1])
+		assert.Equal(t, NewTreeIndexKey(0, 0, 1, 2), indexes[2])
+	})
+}
+
+func TestTreeIndexKey_String_EdgeCases(t *testing.T) {
+	t.Run("all zeros", func(t *testing.T) {
+		key := NewTreeIndexKey(0, 0, 0, 0)
+		assert.Equal(t, "Index(0:0)", key.String())
+	})
+
+	t.Run("single layer both sides", func(t *testing.T) {
+		key := NewTreeIndexKey(0, 0, 1, 1)
+		assert.Equal(t, "Index(0:1)", key.String())
+	})
+
+	t.Run("multiple bottom single top", func(t *testing.T) {
+		key := NewTreeIndexKey(0, 2, 3, 3)
+		assert.Equal(t, "Index(0-2:3)", key.String())
+	})
+
+	t.Run("single bottom multiple top", func(t *testing.T) {
+		key := NewTreeIndexKey(0, 0, 1, 3)
+		assert.Equal(t, "Index(0:1-3)", key.String())
+	})
+
+	t.Run("multiple both sides", func(t *testing.T) {
+		key := NewTreeIndexKey(0, 2, 3, 5)
+		assert.Equal(t, "Index(0-2:3-5)", key.String())
+	})
+}
+
diff --git a/dive/filetree/file_node_test.go b/dive/filetree/file_node_test.go
index a344475..802d862 100644
--- a/dive/filetree/file_node_test.go
+++ b/dive/filetree/file_node_test.go
@@ -166,3 +166,421 @@ func TestDirSize(t *testing.T) {
 		t.Errorf("Expected metadata '%s' got '%s'", expected, actual)
 	}
 }
+
+func TestFileNode_compare(t *testing.T) {
+	t.Run("both nil returns Unmodified", func(t *testing.T) {
+		// Need to call compare on nil receiver
+		var node *FileNode
+		result := node.compare(nil)
+		if result != Unmodified {
+			t.Errorf("Expected Unmodified but got %v", result)
+		}
+	})
+
+	t.Run("non-nil node and nil other returns Removed", func(t *testing.T) {
+		tree := NewFileTree()
+		tree.Root.Name = "test"
+
+		result := tree.Root.compare(nil)
+		if result != Removed {
+			t.Errorf("Expected Removed but got %v", result)
+		}
+	})
+
+	t.Run("whiteout file returns Removed", func(t *testing.T) {
+		tree := NewFileTree()
+		node, _, _ := tree.AddPath("/file.txt", FileInfo{
+			Path:     "/file.txt",
+			TypeFlag: 1,
+			hash:     123,
+		})
+
+		whiteoutNode := &FileNode{
+			Name: ".wh.file.txt",
+			Data: NodeData{
+				FileInfo: FileInfo{
+					Path:     "/.wh.file.txt",
+					TypeFlag: 1,
+				},
+			},
+		}
+
+		result := node.compare(whiteoutNode)
+		if result != Removed {
+			t.Errorf("Expected Removed for whiteout but got %v", result)
+		}
+	})
+
+	t.Run("mismatched node names panic", func(t *testing.T) {
+		tree := NewFileTree()
+		node, _, _ := tree.AddPath("/file1.txt", FileInfo{
+			Path:     "/file1.txt",
+			TypeFlag: 1,
+			hash:     123,
+		})
+
+		other := &FileNode{
+			Name: "file2.txt",
+			Data: NodeData{
+				FileInfo: FileInfo{
+					Path:     "/file2.txt",
+					TypeFlag: 1,
+					hash:     123,
+				},
+			},
+		}
+
+		defer func() {
+			if r := recover(); r == nil {
+				t.Errorf("Expected panic when comparing mismatched nodes")
+			}
+		}()
+
+		node.compare(other)
+	})
+
+	t.Run("same nodes return Unmodified", func(t *testing.T) {
+		tree := NewFileTree()
+		node, _, _ := tree.AddPath("/file.txt", FileInfo{
+			Path:     "/file.txt",
+			TypeFlag: 1,
+			hash:     123,
+			Mode:     0644,
+			Uid:      1000,
+			Gid:      1000,
+		})
+
+		other := &FileNode{
+			Tree: tree,
+			Name: "file.txt",
+			Data: NodeData{
+				FileInfo: FileInfo{
+					Path:     "/file.txt",
+					TypeFlag: 1,
+					hash:     123,
+					Mode:     0644,
+					Uid:      1000,
+					Gid:      1000,
+				},
+			},
+		}
+
+		result := node.compare(other)
+		if result != Unmodified {
+			t.Errorf("Expected Unmodified but got %v", result)
+		}
+	})
+
+	t.Run("different hash returns Modified", func(t *testing.T) {
+		tree := NewFileTree()
+		node, _, _ := tree.AddPath("/file.txt", FileInfo{
+			Path:     "/file.txt",
+			TypeFlag: 1,
+			hash:     123,
+		})
+
+		other := &FileNode{
+			Tree: tree,
+			Name: "file.txt",
+			Data: NodeData{
+				FileInfo: FileInfo{
+					Path:     "/file.txt",
+					TypeFlag: 1,
+					hash:     456,
+				},
+			},
+		}
+
+		result := node.compare(other)
+		if result != Modified {
+			t.Errorf("Expected Modified but got %v", result)
+		}
+	})
+}
+
+func TestFileNode_AddChild_EdgeCases(t *testing.T) {
+	t.Run("add child with existing name", func(t *testing.T) {
+		tree := NewFileTree()
+		payload1 := FileInfo{Path: "/file1"}
+		payload2 := FileInfo{Path: "/file2"}
+
+		node1 := tree.Root.AddChild("test", payload1)
+		node2 := tree.Root.AddChild("test", payload2)
+
+		// Should add a new child even with same name
+		if node1 == nil || node2 == nil {
+			t.Errorf("Expected both nodes to be created")
+		}
+
+		if tree.Root.Children["test"] == nil {
+			t.Errorf("Expected child to exist in tree")
+		}
+	})
+
+	t.Run("add child to nested node", func(t *testing.T) {
+		tree := NewFileTree()
+		parent := tree.Root.AddChild("parent", FileInfo{})
+		child := parent.AddChild("child", FileInfo{Path: "/parent/child"})
+
+		if child == nil {
+			t.Errorf("Expected child to be created")
+		}
+
+		if len(parent.Children) != 1 {
+			t.Errorf("Expected parent to have 1 child, got %d", len(parent.Children))
+		}
+	})
+}
+
+func TestFileNode_Remove_EdgeCases(t *testing.T) {
+	t.Run("remove node with children", func(t *testing.T) {
+		tree := NewFileTree()
+		parent := tree.Root.AddChild("parent", FileInfo{})
+		parent.AddChild("child1", FileInfo{})
+		parent.AddChild("child2", FileInfo{})
+
+		initialSize := tree.Size
+		err := parent.Remove()
+		checkError(t, err, "unable to remove node")
+
+		if tree.Size >= initialSize {
+			t.Errorf("Expected tree size to decrease after removal")
+		}
+	})
+
+	t.Run("remove root node", func(t *testing.T) {
+		tree := NewFileTree()
+		tree.Root.AddChild("child1", FileInfo{})
+		tree.Root.AddChild("child2", FileInfo{})
+
+		err := tree.Root.Remove()
+		// Root removal should fail
+		if err == nil {
+			t.Errorf("Expected error when removing root node")
+		}
+		if err != nil && err.Error() != "cannot remove the tree root" {
+			t.Errorf("Expected 'cannot remove the tree root' error, got: %v", err)
+		}
+	})
+}
+
+func TestFileNode_String(t *testing.T) {
+	t.Run("string representation", func(t *testing.T) {
+		tree := NewFileTree()
+		node, _, _ := tree.AddPath("/test.txt", FileInfo{
+			Path:     "/test.txt",
+			TypeFlag: 1,
+			Mode:     0644,
+			Uid:      1000,
+			Gid:      1000,
+		})
+		node.Data.DiffType = Modified
+
+		str := node.String()
+		if str == "" {
+			t.Errorf("Expected non-empty string representation")
+		}
+	})
+
+	t.Run("string representation for directory", func(t *testing.T) {
+		tree := NewFileTree()
+		node, _, _ := tree.AddPath("/dir", FileInfo{
+			Path:     "/dir",
+			TypeFlag: 1,
+		})
+		node.Data.FileInfo.IsDir = true
+
+		str := node.String()
+		if str == "" {
+			t.Errorf("Expected non-empty string representation for directory")
+		}
+	})
+}
+
+func TestFileNode_MetadataString(t *testing.T) {
+	t.Run("metadata string for regular file", func(t *testing.T) {
+		tree := NewFileTree()
+		node, _, _ := tree.AddPath("/test.txt", FileInfo{
+			Path:     "/test.txt",
+			TypeFlag: 1,
+			Size:     1024,
+			Mode:     0644,
+			Uid:      1000,
+			Gid:      1000,
+		})
+
+		metadata := node.MetadataString()
+		if metadata == "" {
+			t.Errorf("Expected non-empty metadata string")
+		}
+	})
+
+	t.Run("metadata string for directory", func(t *testing.T) {
+		tree := NewFileTree()
+		_, _, err := tree.AddPath("/dir", FileInfo{
+			Path:     "/dir",
+			TypeFlag: 1,
+		})
+		checkError(t, err, "unable to setup test")
+
+		node, _ := tree.GetNode("/dir")
+		node.Data.FileInfo.IsDir = true
+
+		metadata := node.MetadataString()
+		if metadata == "" {
+			t.Errorf("Expected non-empty metadata string for directory")
+		}
+	})
+}
+
+func TestFileNode_GetSize(t *testing.T) {
+	t.Run("get size for regular file", func(t *testing.T) {
+		tree := NewFileTree()
+		node, _, _ := tree.AddPath("/file.txt", FileInfo{
+			Path:     "/file.txt",
+			TypeFlag: 1,
+			Size:     2048,
+		})
+
+		size := node.GetSize()
+		if size != 2048 {
+			t.Errorf("Expected size 2048, got %d", size)
+		}
+	})
+
+	t.Run("get size for directory with children", func(t *testing.T) {
+		tree := NewFileTree()
+		_, _, err := tree.AddPath("/dir", FileInfo{
+			Path:     "/dir",
+			TypeFlag: 1,
+		})
+		checkError(t, err, "unable to setup test")
+
+		node, _ := tree.GetNode("/dir")
+		node.Data.FileInfo.IsDir = true
+
+		tree.AddPath("/dir/file1.txt", FileInfo{Size: 100})
+		tree.AddPath("/dir/file2.txt", FileInfo{Size: 200})
+
+		size := node.GetSize()
+		if size != 300 {
+			t.Errorf("Expected total size 300, got %d", size)
+		}
+	})
+
+	t.Run("get size for empty directory", func(t *testing.T) {
+		tree := NewFileTree()
+		_, _, err := tree.AddPath("/dir", FileInfo{
+			Path:     "/dir",
+			TypeFlag: 1,
+		})
+		checkError(t, err, "unable to setup test")
+
+		node, _ := tree.GetNode("/dir")
+		node.Data.FileInfo.IsDir = true
+
+		size := node.GetSize()
+		if size != 0 {
+			t.Errorf("Expected size 0 for empty directory, got %d", size)
+		}
+	})
+}
+
+func TestFileNode_VisitDepthChildFirst(t *testing.T) {
+	t.Run("visit tree child first", func(t *testing.T) {
+		tree := NewFileTree()
+		tree.AddPath("/dir", FileInfo{})
+		tree.AddPath("/dir/file1.txt", FileInfo{})
+		tree.AddPath("/dir/file2.txt", FileInfo{})
+
+		node, _ := tree.GetNode("/dir")
+
+		var visited []string
+		visitor := func(n *FileNode) error {
+			visited = append(visited, n.Path())
+			return nil
+		}
+		evaluator := func(n *FileNode) bool {
+			return true
+		}
+		sorter := GetSortOrderStrategy(ByName)
+
+		err := node.VisitDepthChildFirst(visitor, evaluator, sorter)
+		checkError(t, err, "unable to visit tree")
+
+		if len(visited) == 0 {
+			t.Errorf("Expected nodes to be visited")
+		}
+	})
+}
+
+func TestFileNode_VisitDepthParentFirst(t *testing.T) {
+	t.Run("visit tree parent first", func(t *testing.T) {
+		tree := NewFileTree()
+		tree.AddPath("/dir", FileInfo{})
+		tree.AddPath("/dir/file1.txt", FileInfo{})
+		tree.AddPath("/dir/file2.txt", FileInfo{})
+
+		node, _ := tree.GetNode("/dir")
+
+		var visited []string
+		visitor := func(n *FileNode) error {
+			visited = append(visited, n.Path())
+			return nil
+		}
+		evaluator := func(n *FileNode) bool {
+			return true
+		}
+		sorter := GetSortOrderStrategy(ByName)
+
+		err := node.VisitDepthParentFirst(visitor, evaluator, sorter)
+		checkError(t, err, "unable to visit tree")
+
+		if len(visited) == 0 {
+			t.Errorf("Expected nodes to be visited")
+		}
+	})
+}
+
+func TestFileNode_AssignDiffType(t *testing.T) {
+	t.Run("assign diff type to node and children", func(t *testing.T) {
+		tree := NewFileTree()
+		tree.AddPath("/dir", FileInfo{})
+		tree.AddPath("/dir/file1.txt", FileInfo{})
+		tree.AddPath("/dir/file2.txt", FileInfo{})
+
+		node, _ := tree.GetNode("/dir")
+
+		err := node.AssignDiffType(Added)
+		checkError(t, err, "unable to assign diff type")
+
+		// Check that the node and its children have the correct diff type
+		if node.Data.DiffType != Added {
+			t.Errorf("Expected node diff type to be Added, got %v", node.Data.DiffType)
+		}
+	})
+}
+
+func TestFileNode_IsLeaf(t *testing.T) {
+	t.Run("leaf node has no children", func(t *testing.T) {
+		tree := NewFileTree()
+		node, _, _ := tree.AddPath("/file.txt", FileInfo{})
+
+		if !node.IsLeaf() {
+			t.Errorf("Expected file node to be a leaf")
+		}
+	})
+
+	t.Run("directory node is not a leaf", func(t *testing.T) {
+		tree := NewFileTree()
+		tree.AddPath("/dir", FileInfo{})
+		tree.AddPath("/dir/file.txt", FileInfo{})
+
+		node, _ := tree.GetNode("/dir")
+
+		if node.IsLeaf() {
+			t.Errorf("Expected directory node to not be a leaf")
+		}
+	})
+}
+