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15.4.3 Incompatibilities with other TAP parsers and drivers

For implementation or historical reasons, the TAP driver and harness as implemented by Automake have some minors incompatibilities with the mainstream versions, which you should be aware of.

• A Bail out! directive doesn’t stop the whole testsuite, but only the test script it occurs in. This doesn’t follow TAP specifications, but on the other hand it maximizes compatibility (and code sharing) with the “hard error” concept of the default parallel-tests driver.
• The version and pragma directives are not supported.
• The --diagnostic-string option of our driver allows to modify the string that introduces TAP diagnostic from the default value of “#”. The standard TAP protocol has currently no way to allow this, so if you use it your diagnostic will be lost to more compliant tools like prove and Test::Harness
• And there are probably some other small and yet undiscovered incompatibilities, especially in corner cases or with rare usages.