googletesting: Software Testing Categorization

Software Testing Categorization

Tuesday, July 14, 2009

Miško HeveryUnit/Smallimplications. Under 1 ms means that your test cannot do any I/O. The reason this is important is that you want to run ALL (thousands) of your unit-tests every time you modify anything, preferably on each save. My patience is two seconds max. In two seconds I want to make sure that all of my unit tests ran and nothing broke. This is a great world to be in, since if tests go red you just hit Ctrl-Z few times to undo what you have done and try again. The immediate feedback is addictive. Not needing a debugger implies that the test is localized (hence the word unit, as in single class).theory of bugsKeyedMultiStackTest.javaTestability ExplorerKeyedMultiStack.javafundamentally flawed. By this time I had most of the project working and this is a key class for byte-code analysis process. How would you feel about ripping out something so fundamental out of your system and rewriting it from scratch? It took me two days to rewrite it until all of my test passed again. After the rewrite the overall application still worked. This is where you have an AHa! moment, when you realize just how amazing unit-tests are.Medium/Functionalindividually, but how do you know that they work together? For this we need to wire related classes together just as they would be in production and exercise some basic execution paths through it. The question here we are trying to answer is not if the 'ifs' and 'loops' work, (we have already answered that,) but whether the interfaces between classes abide by their contracts. Great example of functional test is MetricComputerTest.java. Notice how the input of each test is an inner class in the test file and the output is ClassCost.java. To get the output several classes have to collaborate together to: parse byte-codes, analyze code paths, and compute costs until the final cost numbers are asserted.retroactively to my unit test to 1) prove to myself that I understand the bug and 2) prevent this bug from happening again. The retroactive unit test is the reason why the unit tests at the end of KeyedMultiStackTest.java file are "strange" for a lack of a better world. They are things which I did not think of when i wrote the unit-test, but discovered when I wrote functional tests, and through lot of hours behind debugger track down to KeyedMultiStack.java class as the culprit.Large/End-to-End/ScenarioTestabilityRunnerTest.java

1 comment :

GiorgioJuly 15, 2009 at 7:43 AM
Isn't the method testPopTooSlowForVeryLargeSets() on KeyedMultiStackTest not consistent? Depending on the machine speed it could fail or pass.
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