I'm trying to get my tests to report missing lines and branches. I've configured nose2 and coverage to produce line and branch coverage, and as far as I can tell I have set the coverage config correctly to give me the missing lines and branches. However I can't get coverage to give me missing column when run under nose2, but I can if I run it directly.
Consider the following setup in my project directory.
my_module/
__init__.py
main.py
tests/
test_a_thing.py
unittest.cfg
.coveragerc
contents of .coveragerc
[run]
branch = True
[report]
show_missing = True
contents of unittest.cfg
[coverage]
always-on = True
coverage = my_module
coverage-config = .coveragerc
the output of my nose2 command
(example_venv) andy@batman[11:30:53]:/space/test_example$ python -m nose2 -c unittest.cfg --no-user-config
.
----------------------------------------------------------------------
Ran 1 test in 0.000s
OK
----------- coverage: platform linux, python 3.5.2-final-0 -----------
Name Stmts Miss Branch BrPart Cover
---------------------------------------------------------
my_module/__init__.py 0 0 0 0 100%
my_module/main.py 4 1 2 1 67%
---------------------------------------------------------
TOTAL 4 1 2 1 67%
As you can see, it has given me Branch cover, but not told me the missing branches.
If I simply run coverage report (on the produced .coverage file that is left behind after running nose)
(example_venv) andy@batman[11:34:15]:/space/test_example$ coverage report
Name Stmts Miss Branch BrPart Cover Missing
-------------------------------------------------------------------
my_module/__init__.py 0 0 0 0 100%
my_module/main.py 4 1 2 1 67% 3, 2->3
-------------------------------------------------------------------
TOTAL 4 1 2 1 67%
You can see that coverage has given me the missing branches.
I can tell that coverage is picking up the .coveragerc when run under nose2, because if I remove the branch = True line under the [run] section in .coveragerc, then the branch coverage stats disappear from the report when run under nose.
Am I missing something extra I'm supposed to have done to get this show_missing config to get passed to coverage when it is run under nose2?
versions installed
cov-core==1.15.0
coverage==4.3.4
nose2==0.6.5
tl;dr - have to add coverage-report = term-missing to the [coverage] section in the unittest.cfg (or other --config [CONFIG], -c [CONFIG] file) for nose2. In order for Cov-Core to pass show_missing = True to coverage
Longer explanation:
When running coverage report on the command-line, show_missing is passed into coverage.coverage()* as None unless overridden in the command line arguments.
However nose2 uses cov-core, which will pass show_missing to coverage.coverage()* in cov_core.CovController.summary() as either True or False. Based upon the following logic:
if 'term' in self.cov_report or 'term-missing' in self.cov_report:
show_missing = 'term-missing' in self.cov_report
self.cov.report(show_missing=show_missing, ignore_errors=True, file=stream)
cov_report is that coverage-report config set in nose2.
So this is my confusion because I was trying to use coverage's configs to yield missing lines/branches (when doing a report to term, there's an extra flag for show_missing), when Cov-Core treats them as separate reports (either report term to get plain coverage, or term-missing to get plain coverage + missing lines).
So don't let yourself be bitten by this bit of coverage behaviour Cov-Core has decided to override, when most other bits (include/exclude branch coverage for one) are still driven by coverage's configs.
*coverage.coverage() is a backwards compatability tweak, and is actually an import (in coverage/__init__.py) for coverage.control.Coverage()