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Nobody denies integration tests are good. You just don't want your unit tests to be integration tests. Unit tests are meant to be fast, and quick to isolate th

by UK-AL 10y ago

Nobody denies integration tests are good. You just don't want your unit tests to be integration tests. Unit tests are meant to be fast, and quick to isolate the failing code.

snovv_crash 10y ago
If you make your so-called-'unit' tests too closely coupled to you don't actually work faster though, because you constantly have to refactor them to match the internal implementation. Your testing feedback might be quicker, but quickly getting useless information (ie. your implementation changed) is just as bad as slower tests, because you need to fix the test, recompile and again before you get useful information. Also not all 'integration tests' are slow. If you can test using SQlite in memory, instead of pointing at a PG instance that needs to be provisioned, for instance, you can get a lot of your end-to-end testing running really quickly.
- discreteevent 10y ago
  I agree. Unit tests can definitely slow you down. Testing against high level interfaces or having full integration tests is better. Then the failure is much more likely to be a genuine failure rather than a legitimate change in implementation. If you have good logging and debugging tools the failure can be quite quick to pin down. James Coplien suggests liberal use of assertions in code which is a really good idea and something C/C++ programmers used to do a lot of. Assertions can then be as effective as unit tests in terms of localising failure.
- bradmwalker 10y ago
  Try CREATE TABLE UNLOGGED with postgres. The diversity of RDBMS and SQL dialects defeats the point of integration testing the persistence layer with SQLite.
  - snovv_crash 10y ago
    Yes, but a large portion of code that needs testing is simple inserting, queries and joins, and SQLite can do this without any problems. You can push complex or db-specific work to slower test groups, but not everything requires it.
    - abiox 10y ago
      even this is less clear - for some dbs it's normal to use a sequence for rowid's (vs some sort of autoincrement) and i don't think sqlite offers all the same behavior there.

by UK-AL 10y ago

Nobody denies integration tests are good. You just don't want your unit tests to be integration tests. Unit tests are meant to be fast, and quick to isolate the failing code.

snovv_crash 10y ago

If you make your so-called-'unit' tests too closely coupled to you don't actually work faster though, because you constantly have to refactor them to match the internal implementation. Your testing feedback might be quicker, but quickly getting useless information (ie. your implementation changed) is just as bad as slower tests, because you need to fix the test, recompile and again before you get useful information. Also not all 'integration tests' are slow. If you can test using SQlite in memory, instead of pointing at a PG instance that needs to be provisioned, for instance, you can get a lot of your end-to-end testing running really quickly.

discreteevent 10y ago
I agree. Unit tests can definitely slow you down. Testing against high level interfaces or having full integration tests is better. Then the failure is much more likely to be a genuine failure rather than a legitimate change in implementation. If you have good logging and debugging tools the failure can be quite quick to pin down. James Coplien suggests liberal use of assertions in code which is a really good idea and something C/C++ programmers used to do a lot of. Assertions can then be as effective as unit tests in terms of localising failure.
bradmwalker 10y ago
Try CREATE TABLE UNLOGGED with postgres. The diversity of RDBMS and SQL dialects defeats the point of integration testing the persistence layer with SQLite.
- snovv_crash 10y ago
  Yes, but a large portion of code that needs testing is simple inserting, queries and joins, and SQLite can do this without any problems. You can push complex or db-specific work to slower test groups, but not everything requires it.
  - abiox 10y ago
    even this is less clear - for some dbs it's normal to use a sequence for rowid's (vs some sort of autoincrement) and i don't think sqlite offers all the same behavior there.