add coverage.py module to tests directory.
written by ned batchelder and gareth rees.
abort: impossible time zone offset: 4444444
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abort: invalid date: '1\t15.1'
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abort: invalid date: 'foo bar'
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abort: invalid date: ' 1 4444'
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abort: date exceeds 32 bits: 111111111111
transaction abort!
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abort: No such file or directory: .../test/bar