Failure messages

Every failure follows one template:

Text 
{Format} did not match snapshot: {verified file}
{N} difference(s):
{one block per difference}
(+{M} more, see received)
Received: {received file}
Accept:   snap accept {key}   (or: dnx Nullean.Snapshots.Cli accept {key})
   or:    SNAPSHOT_ACCEPT=1 dotnet test --project {project} --treenode-filter "{filter}"
  • New snapshots start {Format} snapshot is new: no verified file at {verified file} and list no differences.
  • Paths are relative to the repository root (the nearest folder holding .git), with / on every OS.
  • The --treenode-filter line appears with the TUnit adapter, which knows the running test; run as printed, it selects exactly that test.
  • because goes into the first line: JSON did not match snapshot because the catalog is stable: ….

At most 20 differences and 80 lines are shown. A difference that does not fit in the remaining lines is left out whole rather than cut halfway, except a first difference longer than the cap on its own, which is cut so the message still shows something. Everything left out is counted in (+M more, see received); the received file always has everything.

Plain text

No colour codes, ever, and content is never used as a format string, so braces in snapshots are safe. The messages read the same in a terminal, a CI log and an agent's context, and this repository keeps its own messages as golden snapshots.