Use of When and Then in Groovy?

Question

I have been seeing the use of "when" and "then" keyword in Groovy in several Groovy articles. One of them is here. I searched for the Groovy Doc's but I couldn't find it. So whats the actual purposes of these keyword's? Similar to if/then?

score 9 · Accepted Answer · answered Nov 27 '11 at 04:12

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They aren't groovy keywords; they're actually constructs provided by some popular test frameworks. It looks like easyb and spock both use when and then.

In both cases, the test frameworks create a test specification DSL that looks human readable.

answered Nov 27 '11 at 04:12

ataylor

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score 1 · Answer 2 · answered Nov 27 '11 at 02:36

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when and then, among others, seem to be documented here.

answered Nov 27 '11 at 02:36

icktoofay

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score 1 · Answer 3 · answered Nov 27 '11 at 07:53

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Technically the then, when and a few other constructs in Spock are good old labels (aka goto), which developers rarely use these days. Spock uses them to allow developers to logically and visually separate different aspects of their tests - assumptions, constraints, statements or data. The Spock compile-time AST transformations than use the labels to understand the structure of the test and do its magic.

answered Nov 27 '11 at 07:53

Vaclav Pech

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A little confusing that the same label can be used multiple times in the same code block (at least... it is to me!) – Armand Nov 30 '11 at 14:53
Even in Java, the same label can be used multiple times in a row. There is no risk of ambiguity. – Peter Niederwieser Dec 03 '11 at 01:48

Use of When and Then in Groovy?

3 Answers3