Implement group parametrization

[Steap2448]

Implement group parametrization

  -- Define parametrized groups
  local pg = t.group('pgroup', t.helpers.matrix({a = {1, 2}, b = {3, 4}}))
  pg.test_example_1 = function(cg) ... end
  -- type(cg.params.a) == 'number'
  pg.test_example_n = function(cg) ... end

  -- Hooks can be specified for one parameter
  pg.before_all(function() ... end)
  pg.before_each({a = 1}, function() ... end)
  pg.after_each({b = 3}, function() ... end)
  pg.after_test('test_example_1', {a = 2, b = 4}, function() ... end)

Test with specified params can be started from command line

luatest pgroup.a:2.b:3.test_example_1

I didn't forget about

• Tests
• Changelog
• Documentation

Close #116

[rosik]

What about command-line arguments parsing? We discussed it orally. Are you going to implement it in a different PR?

We also discussed restricting types of parameters values. Because group name formatting a.b_1.c_3 doesn't look pretty, and in the case of a table it would be even worse. You can take a look at pytest which luatest was inspired by.

[rosik]

Suggested change

	-- type(cg.params.param_1) == 'number'
	-- type(pg.params.param_1) == 'number'

[Steap2448]

Nope, it's ok

[rosik]

What about key-value tables instead of an array? Is it ever legal?

t.group('parametrized', {param = {key = 'value'}})

[Steap2448]

Illegal and banned

[ligurio]

In PR's description checkbox "Documentation" is checked. But commit doesn't contain any feature description. Could you add a couple of words to the README?

[Steap2448]

In PR's description checkbox "Documentation" is checked. But commit doesn't contain any feature description. Could you add a couple of words to the README?

I have added a new section about parametrization to README. There were some examples already, but it wasn't comprehensive