FLIP — File-Linked Intelligent Pairing

VS Code extension to quickly switch between source and test files. Works out of the box with common conventions and is fully configurable for custom project structures.

Keybindings

Shortcut	Command	Description
Cmd+Shift+T / Ctrl+Shift+T	FLIP: Flip to Test/Source	Toggle between unit test and source file using deterministic candidate matching
Cmd+Shift+A / Ctrl+Shift+A	FLIP: Flip to Related File	Smart search with scoring — finds related files (e.g. acceptance tests) using template matching, fuzzy glob search, and multi-signal scoring
Alt+Shift+T	FLIP: Open Test/Source Side by Side	Same as Flip to Test/Source but opens in a split editor
—	FLIP: Create Test File	Creates a new test file with boilerplate for the current source file

How It Works

Cmd+Shift+T — Deterministic Flip

Generates exact candidate paths by combining configured path mappings with test file prefixes/suffixes. Tries each candidate in order, falling back to a workspace-wide glob search by filename if no exact path exists. Fast and predictable.

Cmd+Shift+A — Smart Scored Search

Uses a multi-phase pipeline to find related files:

1. Template matching — applies flip.relatedMappings templates to resolve exact candidate paths
2. Glob search — searches within configured searchPaths for broader matches
3. Fuzzy keyword search — extracts keywords from the filename and searches for similar files
4. Scoring — ranks all results using six signals:
   • Structural path mirroring (parallel directory trees)
   • LCS-based path segment similarity
   • Core name match (stripped of test affixes)
   • Extension affinity (language-family compatibility)
   • Direction indicators (test vs. source directory)
   • Keyword word overlap

If the top result is clearly best (score gap > 20), it opens automatically. Otherwise a QuickPick shows the ranked candidates.

Supported Patterns (Defaults)

• test_ / ut_ prefix — src/modules/X/foo.cpp ↔ test/modules/X/test_foo.cpp
• _test suffix — foo.go ↔ foo_test.go
• .test. / .spec. suffix — app.ts ↔ app.test.ts
• Java Test prefix/suffix — Foo.java ↔ TestFoo.java / FooTest.java
• Directory mirroring — src/ ↔ test/, src/main/java ↔ src/test/java, lib/ ↔ test/, etc.

Configuration

All settings are under flip.* in VS Code settings.

flip.pathMappings

Directory segment pairs for source ↔ test mirroring. Order matters — first match wins.

"flip.pathMappings": [
  { "source": "src/modules", "test": "test/modules" },
  { "source": "src/main/java", "test": "src/test/java" },
  { "source": "src/main/kotlin", "test": "src/test/kotlin" },
  { "source": "lib", "test": "test" },
  { "source": "src", "test": "__tests__" },
  { "source": "src", "test": "test" }
]

flip.testFilePrefixes / flip.testFileSuffixes

Filename conventions that identify test files:

"flip.testFilePrefixes": ["test_", "ut_"],
"flip.testFileSuffixes": ["_test", ".test", ".spec"]

flip.javaStyle

Enable TestFoo / FooTest detection (default: true).

flip.relatedMappings

Template-based mappings for related files (e.g. acceptance tests, e2e tests) used by Cmd+Shift+A. Each mapping has:

Field	Type	Description
source	string	Source path template with {name} (one segment) or {path} (multi-segment) placeholders
test	string	Test path template using the same placeholders
filePrefix	string	Filename prefix for related files (e.g. at_, e2e_)
searchPaths	string[]	Glob patterns that scope the fuzzy search to specific directories

"flip.relatedMappings": [
  {
    "source": "components/{comp}/src/modules/{path}",
    "test": "test/at_components/{comp}/{path}",
    "filePrefix": "at_",
    "searchPaths": ["**/test/at_components/**"]
  },
  {
    "source": "components/{comp}/src",
    "test": "test/at_components/{comp}",
    "filePrefix": "at_",
    "searchPaths": ["**/test/at_components/**"]
  }
]

Examples

Ruby/RSpec

{
  "flip.pathMappings": [{ "source": "lib", "test": "spec" }],
  "flip.testFilePrefixes": [],
  "flip.testFileSuffixes": ["_spec"],
  "flip.javaStyle": false
}

Python/pytest

{
  "flip.pathMappings": [{ "source": "src", "test": "tests" }],
  "flip.testFilePrefixes": ["test_"],
  "flip.testFileSuffixes": [],
  "flip.javaStyle": false
}

Scoped smart search with searchPaths only

The simplest way to use Cmd+Shift+A is to provide only searchPaths — no templates needed. The fuzzy keyword search + scoring will find related files within those directories:

{
  "flip.relatedMappings": [
    {
      "searchPaths": ["**/integration/tests/**"]
    }
  ]
}

This makes Cmd+Shift+A search for related files only inside integration/tests/, using filename keywords and scoring to find the best match.

Scoped smart search with full template mapping

For more precise matching, add source/test templates and a filePrefix. This enables exact candidate resolution in addition to fuzzy search:

{
  "flip.relatedMappings": [
    {
      "source": "src/{path}",
      "test": "integration/tests/{path}",
      "filePrefix": "test_",
      "searchPaths": ["**/integration/tests/**"]
    }
  ]
}

flip.testTemplates

Custom boilerplate templates used when creating new test files. Each entry maps file extensions to a template string. If no template matches, built-in defaults are used.

Placeholder	Expands to
{name}	Source filename without extension (e.g. parser)
{Name}	Capitalized source name (e.g. Parser)
{className}	Test filename without extension (e.g. test_parser)
{package}	Parent directory name (e.g. utils)

Use \n for newlines in the template string.

"flip.testTemplates": [
  {
    "extensions": [".cpp", ".h"],
    "template": "#include \"{name}.h\"\n\nTEST({Name}, ShouldWork) {\n\n}\n"
  },
  {
    "extensions": [".ts", ".tsx"],
    "template": "import { {name} } from './{name}';\n\ndescribe('{name}', () => {\n  it('should work', () => {\n\n  });\n});\n"
  },
  {
    "extensions": [".py"],
    "template": "import pytest\nfrom {package}.{name} import *\n\n\ndef test_{name}():\n    pass\n"
  }
]

With this configuration, Cmd+Shift+A first tries exact template matching, then falls back to fuzzy search scoped to integration/tests/. For example:

• src/services/auth.ts → finds integration/tests/services/test_auth.ts

Installation

npm install && npm run compile
npm run package

Then install via Extensions → Install from VSIX…

Development

npm run watch    # compile on change
npm test         # run unit tests

Press F5 in VS Code to launch an Extension Development Host.