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Diff Viewer UI / CLI

Difflicious CLI provides both interactive and non-interactive viewing of diffs generated by the tests failures.

You can interactively explore diffs from test failures by launching in TUI (Terminal user interface) mode. For non-interactive use cases such as for LLM AIs, you can view the diffs in plain (human readable) or JSON format.

If you are using Difflicious' sbt-difflicious plugin, running diffliciousViewer command will launch the TUI / CLI.

About test diff reports​

With the SBT plugin loaded and configured for your test framework, each failing diff test will generate a test report as a JSONL file.

runId: Whenever you run test, testOnly etc in SBT, a new test runId will be generated and passed to the test framework. The runId is a ULID value that uniquely identifies each test run and has a timestamp embedded in it.

testId: Each test failure will generate a unique testId. You can use testId to jump straight to the diff result for that failed test.

Interactive TUI​

By default, the CLI launches in TUI (Terminal User Interface) mode. You can search for tests and interactively explore the differences. Only failures from the latest detected test run are shown. Pass --all-runs to include failures from older runs.

sbt> diffliciousViewer

Search for and select a test failure:

Explore the selected diff:

Hotkeys​

Here are some TUI hotkeys. In general, vim-style keybindings are provided too.

HotkeyAction
↑ / k, ↓ / jMove the selection up or down
Enter / oOpen or toggle the selected entry
← / h, → / lCollapse or expand the selected field
f / bJump to the next or previous difference
/Search field names and values in the current diff
F6Toggle search between fields and values, values only, and fields only
n / NJump to the next or previous search result
F4Clear field search highlighting
aAnchor the selected subtree as the root. Useful if you want to "zoom in" on a particular part of the diff)
tReset anchoring and return to showing the root of the diff
? / F1Show the complete hotkey reference
EscGo back or confirm quit
Ctrl+C / Ctrl+DQuit immediately

Non-interactive mode​

Non-interactive mode is useful for quickly viewing a diff.

There are two modes:

  • Plain (--plain): Plain text format useful for both humans and AI agents
  • JSON (--json): If you need programmatic rendering of the diff details

Plain text output (--plain)​

To print failures from the latest detected test run as plain text:

sbt> diffliciousViewer --plain

To include failures from every detected test run, pass --all-runs:

sbt> diffliciousViewer --plain --all-runs

To print only the failure with a specific test id:

sbt> diffliciousViewer --plain --test-id 01ARZ3NDEKTSV4RRFFQ69G5FAW

The plain output includes test metadata, a summary, and each difference. For example:

Difflicious diff report: different
Summary: 1 diff failure(s), 6 non-ignored change(s).

Failure 1: example.OrderSuite / order snapshot matches
Run id: 01ARZ3NDEKTSV4RRFFQ69G5FAV
Test id: 01ARZ3NDEKTSV4RRFFQ69G5FAW
Location: /workspace/OrderSuite.scala:37
Difflicious diff result: different
Summary: 6 non-ignored change(s), 1 ignored subtree(s).

Differences:
1. $.customer.email - changed
   obtained: "alice@old.example"
   expected: "alice@example.com"

2. $.customer.loyaltyTier - ignored

3. $.shipping.city - changed
   obtained: "London"
   expected: "Bristol"

4. $.lines[0].quantity - changed
   obtained: 1
   expected: 2

5. $.lines[1] - obtained_only (OrderLine)
   obtained:
      OrderLine(
        sku: "SKU-OLD",
        description: "Discontinued lid",
        quantity: 1,
        unitCents: 499
      )

6. $.status - changed
   obtained: "processing"
   expected: "shipped"

7. $.notes[0] - expected_only
   expected: "Leave with reception"