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kward / shunit2

shUnit2 is a xUnit based unit test framework for Bourne based shell scripts.

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Clarification on `oneTimeSetUp()` in `shunit2`

adamgranthendry opened this issue · comments

commented

I'm trying to understand when and how oneTimeSetUp() is called in shunit2. At the end (lines 1371-1374), I see it gets called like so:

# Execute the oneTimeSetUp function (if it exists).
if ! oneTimeSetUp; then
  _shunit_fatal "oneTimeSetUp() returned non-zero return code."
fi

but wouldn't this also fail if oneTimeSetUp() doesn't exist? If it doesn't, oneTimeSetUp would be '' (i.e. NULL) and ! '' evaluates to true (i.e. test '' returns a non-zero error code).

I would have expected this to be

# Execute the oneTimeSetUp function (if it exists).
if type oneTimeSetUp >/dev/null 2>&1 && ! oneTimeSetUp; then
  _shunit_fatal "oneTimeSetUp() returned non-zero return code."
fi

How does the code work without erroring when no oneTimeSetUp() exists? The same question applies to the segment of code in shunit2 that calls oneTimeTearDown().

commented

The _shunit_mktempFunc() function generates stub functions that are written to disk as executables.
https://github.com/kward/shunit2/blob/master/shunit2#L939

It is called as part of the main of shUnit2 during startup so that those functions exist, even if the script doesn't have them.
https://github.com/kward/shunit2/blob/master/shunit2#L1302

If the functions exist in the script, shells will use the local function over any function in the path, which is what I'm taking advantage of here.