diff --git a/pkg/gui/filetree/build_tree_test.go b/pkg/gui/filetree/build_tree_test.go
new file mode 100644
index 000000000..7f702cd1e
--- /dev/null
+++ b/pkg/gui/filetree/build_tree_test.go
@@ -0,0 +1,484 @@
+package filetree
+
+import (
+	"testing"
+
+	"github.com/jesseduffield/lazygit/pkg/commands/models"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestBuildTreeFromFiles(t *testing.T) {
+	scenarios := []struct {
+		name     string
+		files    []*models.File
+		expected *FileNode
+	}{
+		{
+			name:  "no files",
+			files: []*models.File{},
+			expected: &FileNode{
+				Path:     "",
+				Children: []*FileNode{},
+			},
+		},
+		{
+			name: "files in same directory",
+			files: []*models.File{
+				{
+					Name: "dir1/a",
+				},
+				{
+					Name: "dir1/b",
+				},
+			},
+			expected: &FileNode{
+				Path: "",
+				Children: []*FileNode{
+					{
+						Path: "dir1",
+						Children: []*FileNode{
+							{
+								File: &models.File{Name: "dir1/a"},
+								Path: "dir1/a",
+							},
+							{
+								File: &models.File{Name: "dir1/b"},
+								Path: "dir1/b",
+							},
+						},
+					},
+				},
+			},
+		},
+		{
+			name: "paths that can be compressed",
+			files: []*models.File{
+				{
+					Name: "dir1/a",
+				},
+				{
+					Name: "dir2/b",
+				},
+			},
+			expected: &FileNode{
+				Path: "",
+				Children: []*FileNode{
+					{
+						File:             &models.File{Name: "dir1/a"},
+						Path:             "dir1/a",
+						CompressionLevel: 1,
+					},
+					{
+						File:             &models.File{Name: "dir2/b"},
+						Path:             "dir2/b",
+						CompressionLevel: 1,
+					},
+				},
+			},
+		},
+		{
+			name: "paths that can be sorted",
+			files: []*models.File{
+				{
+					Name: "b",
+				},
+				{
+					Name: "a",
+				},
+			},
+			expected: &FileNode{
+				Path: "",
+				Children: []*FileNode{
+					{
+						File: &models.File{Name: "a"},
+						Path: "a",
+					},
+					{
+						File: &models.File{Name: "b"},
+						Path: "b",
+					},
+				},
+			},
+		},
+		{
+			name: "paths that can be sorted including a merge conflict file",
+			files: []*models.File{
+				{
+					Name: "b",
+				},
+				{
+					Name:              "z",
+					HasMergeConflicts: true,
+				},
+				{
+					Name: "a",
+				},
+			},
+			expected: &FileNode{
+				Path: "",
+				// it is a little strange that we're not bubbling up our merge conflict
+				// here but we are technically still in in tree mode and that's the rule
+				Children: []*FileNode{
+					{
+						File: &models.File{Name: "a"},
+						Path: "a",
+					},
+					{
+						File: &models.File{Name: "b"},
+						Path: "b",
+					},
+					{
+						File: &models.File{Name: "z", HasMergeConflicts: true},
+						Path: "z",
+					},
+				},
+			},
+		},
+	}
+
+	for _, s := range scenarios {
+		s := s
+		t.Run(s.name, func(t *testing.T) {
+			result := BuildTreeFromFiles(s.files)
+			assert.EqualValues(t, s.expected, result)
+		})
+	}
+}
+
+func TestBuildFlatTreeFromFiles(t *testing.T) {
+	scenarios := []struct {
+		name     string
+		files    []*models.File
+		expected *FileNode
+	}{
+		{
+			name:  "no files",
+			files: []*models.File{},
+			expected: &FileNode{
+				Path:     "",
+				Children: []*FileNode{},
+			},
+		},
+		{
+			name: "files in same directory",
+			files: []*models.File{
+				{
+					Name: "dir1/a",
+				},
+				{
+					Name: "dir1/b",
+				},
+			},
+			expected: &FileNode{
+				Path: "",
+				Children: []*FileNode{
+					{
+						File:             &models.File{Name: "dir1/a"},
+						Path:             "dir1/a",
+						CompressionLevel: 0,
+					},
+					{
+						File:             &models.File{Name: "dir1/b"},
+						Path:             "dir1/b",
+						CompressionLevel: 0,
+					},
+				},
+			},
+		},
+		{
+			name: "paths that can be compressed",
+			files: []*models.File{
+				{
+					Name: "dir1/a",
+				},
+				{
+					Name: "dir2/b",
+				},
+			},
+			expected: &FileNode{
+				Path: "",
+				Children: []*FileNode{
+					{
+						File:             &models.File{Name: "dir1/a"},
+						Path:             "dir1/a",
+						CompressionLevel: 1,
+					},
+					{
+						File:             &models.File{Name: "dir2/b"},
+						Path:             "dir2/b",
+						CompressionLevel: 1,
+					},
+				},
+			},
+		},
+		{
+			name: "paths that can be sorted",
+			files: []*models.File{
+				{
+					Name: "b",
+				},
+				{
+					Name: "a",
+				},
+			},
+			expected: &FileNode{
+				Path: "",
+				Children: []*FileNode{
+					{
+						File: &models.File{Name: "a"},
+						Path: "a",
+					},
+					{
+						File: &models.File{Name: "b"},
+						Path: "b",
+					},
+				},
+			},
+		},
+		{
+			name: "paths that can be sorted including a merge conflict file",
+			files: []*models.File{
+				{
+					Name:              "z",
+					HasMergeConflicts: true,
+				},
+				{
+					Name: "b",
+				},
+				{
+					Name: "a",
+				},
+			},
+			expected: &FileNode{
+				Path: "",
+				Children: []*FileNode{
+					{
+						File: &models.File{Name: "z", HasMergeConflicts: true},
+						Path: "z",
+					},
+					{
+						File: &models.File{Name: "a"},
+						Path: "a",
+					},
+					{
+						File: &models.File{Name: "b"},
+						Path: "b",
+					},
+				},
+			},
+		},
+	}
+
+	for _, s := range scenarios {
+		s := s
+		t.Run(s.name, func(t *testing.T) {
+			result := BuildFlatTreeFromFiles(s.files)
+			assert.EqualValues(t, s.expected, result)
+		})
+	}
+}
+
+func TestBuildTreeFromCommitFiles(t *testing.T) {
+	scenarios := []struct {
+		name     string
+		files    []*models.CommitFile
+		expected *CommitFileNode
+	}{
+		{
+			name:  "no files",
+			files: []*models.CommitFile{},
+			expected: &CommitFileNode{
+				Path:     "",
+				Children: []*CommitFileNode{},
+			},
+		},
+		{
+			name: "files in same directory",
+			files: []*models.CommitFile{
+				{
+					Name: "dir1/a",
+				},
+				{
+					Name: "dir1/b",
+				},
+			},
+			expected: &CommitFileNode{
+				Path: "",
+				Children: []*CommitFileNode{
+					{
+						Path: "dir1",
+						Children: []*CommitFileNode{
+							{
+								File: &models.CommitFile{Name: "dir1/a"},
+								Path: "dir1/a",
+							},
+							{
+								File: &models.CommitFile{Name: "dir1/b"},
+								Path: "dir1/b",
+							},
+						},
+					},
+				},
+			},
+		},
+		{
+			name: "paths that can be compressed",
+			files: []*models.CommitFile{
+				{
+					Name: "dir1/a",
+				},
+				{
+					Name: "dir2/b",
+				},
+			},
+			expected: &CommitFileNode{
+				Path: "",
+				Children: []*CommitFileNode{
+					{
+						File:             &models.CommitFile{Name: "dir1/a"},
+						Path:             "dir1/a",
+						CompressionLevel: 1,
+					},
+					{
+						File:             &models.CommitFile{Name: "dir2/b"},
+						Path:             "dir2/b",
+						CompressionLevel: 1,
+					},
+				},
+			},
+		},
+		{
+			name: "paths that can be sorted",
+			files: []*models.CommitFile{
+				{
+					Name: "b",
+				},
+				{
+					Name: "a",
+				},
+			},
+			expected: &CommitFileNode{
+				Path: "",
+				Children: []*CommitFileNode{
+					{
+						File: &models.CommitFile{Name: "a"},
+						Path: "a",
+					},
+					{
+						File: &models.CommitFile{Name: "b"},
+						Path: "b",
+					},
+				},
+			},
+		},
+	}
+
+	for _, s := range scenarios {
+		s := s
+		t.Run(s.name, func(t *testing.T) {
+			result := BuildTreeFromCommitFiles(s.files)
+			assert.EqualValues(t, s.expected, result)
+		})
+	}
+}
+
+func TestBuildFlatTreeFromCommitFiles(t *testing.T) {
+	scenarios := []struct {
+		name     string
+		files    []*models.CommitFile
+		expected *CommitFileNode
+	}{
+		{
+			name:  "no files",
+			files: []*models.CommitFile{},
+			expected: &CommitFileNode{
+				Path:     "",
+				Children: []*CommitFileNode{},
+			},
+		},
+		{
+			name: "files in same directory",
+			files: []*models.CommitFile{
+				{
+					Name: "dir1/a",
+				},
+				{
+					Name: "dir1/b",
+				},
+			},
+			expected: &CommitFileNode{
+				Path: "",
+				Children: []*CommitFileNode{
+					{
+						File:             &models.CommitFile{Name: "dir1/a"},
+						Path:             "dir1/a",
+						CompressionLevel: 0,
+					},
+					{
+						File:             &models.CommitFile{Name: "dir1/b"},
+						Path:             "dir1/b",
+						CompressionLevel: 0,
+					},
+				},
+			},
+		},
+		{
+			name: "paths that can be compressed",
+			files: []*models.CommitFile{
+				{
+					Name: "dir1/a",
+				},
+				{
+					Name: "dir2/b",
+				},
+			},
+			expected: &CommitFileNode{
+				Path: "",
+				Children: []*CommitFileNode{
+					{
+						File:             &models.CommitFile{Name: "dir1/a"},
+						Path:             "dir1/a",
+						CompressionLevel: 1,
+					},
+					{
+						File:             &models.CommitFile{Name: "dir2/b"},
+						Path:             "dir2/b",
+						CompressionLevel: 1,
+					},
+				},
+			},
+		},
+		{
+			name: "paths that can be sorted",
+			files: []*models.CommitFile{
+				{
+					Name: "b",
+				},
+				{
+					Name: "a",
+				},
+			},
+			expected: &CommitFileNode{
+				Path: "",
+				Children: []*CommitFileNode{
+					{
+						File: &models.CommitFile{Name: "a"},
+						Path: "a",
+					},
+					{
+						File: &models.CommitFile{Name: "b"},
+						Path: "b",
+					},
+				},
+			},
+		},
+	}
+
+	for _, s := range scenarios {
+		s := s
+		t.Run(s.name, func(t *testing.T) {
+			result := BuildFlatTreeFromCommitFiles(s.files)
+			assert.EqualValues(t, s.expected, result)
+		})
+	}
+}