DELIVERABLES - Twin Commander (P015)

Summary

Twin Commander is a Norton Commander / Midnight Commander style dual-pane terminal file explorer built in Go using the tview library. It provides keyboard-driven navigation, real-time search/filter, color-coded file types, and cross-platform terminal support. Ships as a single static binary with zero runtime dependencies.

Files Delivered

Technology

• Language: Go 1.24
• TUI Framework: github.com/rivo/tview v0.42.0
• Terminal: github.com/gdamore/tcell/v2 v2.13.8
• Test runner: go test
• External dependencies: tview, tcell (and their transitive deps)

Test Results (from go test -v ./... output)

# tests 64
# pass 64
# fail 0
ok  twin-commander  0.005s

Test Breakdown

format_test.go (7 tests)

• TestFormatSize_Bytes — TS-19
• TestFormatSize_Kilobytes — TS-20
• TestFormatSize_MegabytesAndGigabytes — TS-21
• TestFormatSize_BoundaryValues — EC-5
• TestFormatSize_ZeroByte — EC-6
• TestFormatSize_VeryLargeFiles — EC-7
• TestFormatSize_InaccessibleSentinel — EC-18

• TestFilterEntries_CaseInsensitive — TS-29
• TestFilterEntries_MatchesNothing — EC-10
• TestFilterEntries_DotDotNeverFiltered — TS-43
• TestFilterEntries_EmptyQuery
• TestFilterEntries_SubstringMatch

• TestSortEntries_DirectoriesFirstThenFiles — TS-18
• TestSortEntries_CaseInsensitive — EC-15
• TestSortEntries_StableSort
• TestSortEntries_BrokenSymlinkWithFiles — EC-11 (sort)
• TestReadEntries_BasicDirectory (integration)
• TestReadEntries_HiddenFilesOff (integration)
• TestReadEntries_HiddenFilesOn (integration)
• TestReadEntries_FileMetadata (integration)
• TestReadEntries_ExecutableDetection (integration)
• TestReadEntries_Symlinks (integration)
• TestReadEntries_BrokenSymlink — EC-11 (integration)
• TestReadEntries_NonexistentDir
• TestFileEntry_DateFormat
• TestReadEntries_DirectoriesNotExecutable

• TestPanel_LoadDir — directory loading
• TestPanel_LoadDir_SortOrder — verified sort: .., dirs, files
• TestPanel_LoadDir_AtRoot — EC-2
• TestPanel_NavigateInto — TS-10
• TestPanel_NavigateInto_ClearsFilter — TS-30
• TestPanel_NavigateUp — TS-13
• TestPanel_NavigateUp_CursorPosition — TS-14
• TestPanel_NavigateUp_ClearsFilter — TS-30
• TestPanel_NavigateUp_AtRoot — EC-9
• TestPanel_ToggleHidden — TS-24
• TestPanel_SetFilter — TS-26
• TestPanel_SetFilter_StatusBarUpdates — TS-26 count
• TestPanel_ClearFilter — TS-27
• TestPanel_Refresh — TS-33
• TestPanel_Refresh_PreservesCursor — TS-33 cursor
• TestPanel_Refresh_EntryDisappears — EC-19
• TestPanel_Refresh_ReappliesFilter — FR-16
• TestPanel_StatusText — TS-16
• TestPanel_StatusText_HiddenIndicator — TS-42
• TestPanel_StatusText_NoHiddenIndicator — TS-23
• TestPanel_SetActive — FR-3
• TestPanel_TitleUpdates — FR-8
• TestPanel_TitleUpdatesOnNavigation — TS-15
• TestPanel_NavigateInto_Inaccessible — TS-37/38
• TestPanel_DotDotNoSlashSuffix — FR-2
• TestPanel_DotDotEmptySizeAndDate — FR-2
• TestPanel_DirectorySlashSuffix — FR-2
• TestPanel_FileNoSlashSuffix — FR-2
• TestPanel_SymlinkToDirRendering — FR-19
• TestPanel_BrokenSymlinkRendering — EC-11
• TestPanel_StatusText_InaccessibleEntries — FR-9
• TestPanel_EmptyDirectory — EC-1
• TestPanel_FilterWithHiddenToggle — EC-13
• TestPanel_SelectedEntry — panel selection
• TestPanel_LoadDir_ErrorSetsStatus — ERR-2
• TestPanel_TableRowCount — rendering correctness
• TestPanel_DateColumnFormat — FR-2 date format
• TestPanel_StatusText_PreciseFormat — FR-9 precise values

Test Scenario Coverage

Programmatic Scenarios (tested with go test)

Terminal Scenarios (require running ./twin-commander)

Functional Requirements Coverage

Nice-to-Have Features

Implemented

• FR-15: Search/Filter — full implementation with filter mode, case-insensitive substring matching, Enter to keep filter, Escape to clear, auto-clear on navigation, pre-fill on reopen

Deferred

• None. All specified features are implemented.

Non-Functional Requirements

Integration Tests

All panel tests and entry tests use real temporary directories (via t.TempDir()), real filesystem operations, and real symlinks. No mocking of filesystem calls. This satisfies the integration testing requirement for modules that interact with the filesystem.

Architecture

main.go → NewApp() → App.Run()
                      ├── LeftPanel (tview.Table + Panel state)
                      ├── RightPanel (tview.Table + Panel state)
                      ├── FilterInput (tview.InputField, hidden by default)
                      └── InputCapture (key dispatch: normal/filter mode)

Panel.LoadDir() → ReadEntries() → SortEntries() → FilterEntries() → renderTable()

Build & Run

cd projects/015-twin-commander/3-development
go build -o twin-commander .
go test -v ./...
./twin-commander

Project Status

Complete. All 20 functional requirements implemented. 64 tests pass. Binary builds and runs. Documentation written.