Mock Ignores Call Arguments

What goes wrong

A mock or stub answers an outgoing call without recording or matching the arguments that determine the real answer — matched on path only, on the last argument, on a fragment, or on nothing — so a dropped header, a swapped parameter or a call to the wrong target passes every test.

Example

The payment mock returns 'ok' for any call, so code that sends the amount in dollars instead of cents passes every test.

Not to be confused with

The call is reached and answered; not test data that never reaches the call (Unreached Branch Test), not an expected value copied from the implementation (Self Derived Expected Value), and not a mock whose behaviour differs from the real dependency (Test Double Contract Diverges From Real).

Discovered by

@sks24git GitHub

Field notes · 11

@sks24git2026-11-05

A new parameter is added to a fetched address in code, but the test stub answers every address the same way. Drop the parameter, or build the address wrong, and every test still passes.

Make a fake server record what it was asked. A stub that ignores the request can never fail on it.

@sks24git2026-10-23beat 1 review round

A ready-made client text rephrased a filing deadline as 'before the payment deadline', but the filing date comes days earlier. A client who files between the two dates is late while the text says they are on time.

Never paraphrase a legal deadline into a relative one. 'Before X' hides the real date; say the date comes from code.

@sks24git2026-10-22beat 3 review rounds

Tests faked the restore tool and ignored its flags, so the flags that make a failed restore abort were never checked. Drop one and a failed restore reports success, and the system switches to an empty store.

Make fakes honor the flags that guard data. A fake that ignores them lets the guard vanish.
Verify a copy by reading it back. Exit codes alone can lie.

@sks24git2026-10-21

A test double answered every request by its path alone and never read the body it was sent. A renamed field or a flipped sign on a debt balance passed every test, and only the real server would have refused it.

Make a fake reject what the real server rejects. A double that accepts any body hides contract drift until production.

@sks24git2026-09-15beat 1 review round

A new comment explained why a helper avoids its neighbour: 'its answer changes between two runs.' That was measured without the env var the same change now makes everyone export; with it set, the neighbour is stable.

Date a measurement by its conditions. A number taken before your change may be false after it.
A stub that only fails proves only the failure path. Drive the success path too.

@sks24git2026-09-13

The call under test set three parameters and the new test pinned two of them. The third could be dropped or renamed and the suite stayed green, so half the door the ticket was about had no lock.

Count the inputs of the call, then count your assertions. A test that pins most of a call leaves the rest free to change in silence.

@sks24git2026-09-13beat 1 review round

A fix threaded one optional argument through three calls, and the test entered at the last one and built that argument by hand. Delete the argument at either earlier hop: it compiles, every test stays green.

Test wiring from the end where it begins. A case that enters at the sink pins the sink, not the path to it.

@sks24git2026-09-12beat 6 review rounds

A loop skipped candidates another door refuses, and its own doc named two such states — one had a fixture. Rewrite that guard defensively and both tests stay green while the loop hands back a rejected pointer.

Every state a comment names deserves a fixture. A documented case with no test is a promise, not a guard.
Pin the skip, not only the hit.

@sks24git2026-09-12beat 1 review round

A test mock recorded a command's arguments by joining them with spaces. Drop the quotes around one header and it splits into four arguments that join back to the same string, so the broken call ships green.

Record structure, assert structure. A flattened capture cannot fail on the boundary the bug moves.
Name the mutation a test must catch, then actually run it.

@sks24git2026-09-10beat 1 review round

The only test inspecting a credit call matched its priority and mandatory operator comment with a wildcard. Dropping the comment or changing the priority to a different class passes untouched.

A wildcard in an assertion is an untested argument. Pin the values that carry meaning downstream.

@sks24git2026-09-08

A gate preferred a clean sibling checkout over the caller's own dirty tree, then judged records keyed on the caller's diff from the wrong directory. The caller's hunt was never found and the merge blocked.

Add evidence; never swap the subject being judged. The tree that ran the command is the tree its records are keyed on.
A shim must check the argv it is asked.