Rmocks

Want to provide contained coverage for your R code? RMocks enables mocking on methods of R5 classes

Installation

Clone the git repo and run R CMD INSTALL rmocks

or

use the install_git function from R devtools(https://github.com/hadley/devtools) - install_git("https://github.com/jpsimonroy/rmocks")

Usage

library("testthat")

context("Examples")

before_each=function(){
	setRefClass("IntegrationClass", 
		fields=list(name="character"),
		methods=list(
			method1=function(){
				return("Method1");
			},
			method2=function(argument1, argument2){
				return(paste(argument1, argument2, sep=""))
			}
		),
	);
}


# Use this only if you need to replace a method defn. 
# Restrain from this usage if possible.

context("spy and expects")

test_that("Create a spy and mock a method", {
	before_each();
	model=spy("IntegrationClass", list(method1=function(){
		return("Something else");
	}));
	expect_equal(model$method1(), "Something else");
});

test_that("Use mocks to assert method invocations",{
	before_each();
	model=spy("IntegrationClass");

	model_fixed_params=model$expects("method1", list(1,2), "Return");
	model_fixed_params=model_fixed_params$expects("method2", list("arg1", "arg2"), "Arg1&Arg2");
	# invalid method invocation 
	expect_error(model_fixed_params$method1());
	# call matches expectations
	expect_equal(model_fixed_params$method1(1,2), "Return");
	# method2 expected to be called but never
	expect_false(model_fixed_params$realize_expectations());
	# call the method which was expected.
	expect_equal(model_fixed_params$method2("arg1", "arg2"), "Arg1&Arg2")
	# all expectations are matched now.
	expect_true(model_fixed_params$realize_expectations());


	# setup method invocation match with * params
	model_wild_match=model$expects("method2", returns="Default")
	expect_equal(model_wild_match$method2(1), "Default");
	expect_equal(model_wild_match$method2(1,2), "Default");
	expect_equal(model_wild_match$method2(), "Default");
	expect_true(model_fixed_params$realize_expectations());
});

context("stub and stubs")

#Since no assertions are being made, this should be ok.

test_that("Create a stub and stub a method", {
	before_each();
	model=stub("IntegrationClass", list(method1=function(){
		return("Something else");
	}));
	expect_equal(model$method1(), "Something else");
});

test_that("Use stubs to match arguments and return values",{
	before_each();
	model_strict=stub("IntegrationClass", strict=T);
	model=stub("IntegrationClass");

	model_stubbed_strict=model_strict$stubs("method1", list(1,2), "Return");
	model_stubbed_strict=model_stubbed_strict$stubs("method2", list("arg1", "arg2"), "Arg1&Arg2");
	# invalid method invocation 
	expect_error(model_stubbed_strict$method1());
	# call matches expectations
	expect_equal(model_stubbed_strict$method1(1,2), "Return");
	expect_equal(model_stubbed_strict$method2("arg1", "arg2"), "Arg1&Arg2")

	model_stubbed=model$stubs("method1", list(1,2), "Return");
	model_stubbed=model_stubbed$stubs("method2", list("arg1", "arg2"), "Arg1&Arg2");
	# invalid method invocation returns NA
	expect_true(is.na(model_stubbed$method1()));

	# call matches expectations
	expect_equal(model_stubbed$method1(1,2), "Return");
	expect_equal(model_stubbed$method2("arg1", "arg2"), "Arg1&Arg2")


	# setup method invocation match with * params
	model_wild_match=model$stubs("method2", returns="Default")
	expect_equal(model_wild_match$method2(1), "Default");
	expect_equal(model_wild_match$method2(1,2), "Default");
	expect_equal(model_wild_match$method2(), "Default");
});

Known Issues

1. Expectations do not match when using libraries like multicore in code under test. To work around, alias mclapply with lapply in test mode.
2. When expecting, instance variables on existing model are lost. So assign class variables post setting up all mocks.

setRefClass("IntegrationClass", 
		fields=list(name="character"),
		methods=list(
			method1=function(){
				return("Method1");
			},
			method2=function(argument1, argument2){
				return(paste(argument1, argument2, sep=""))
			}
		),
	);
test_that("Test class assignment",{
	model_strict=stub("IntegrationClass", strict=T);
	model_strict=model_strict$stubs("method1", list(1,2), "Return");
	model_strict$name="IntegrationClass" # OK
	... Test continues
})

test_that("Test class assignment",{
	model_strict=stub("IntegrationClass", strict=T);
	model_strict$name="IntegrationClass" # NOT OK
	model_strict=model_strict$stubs("method1", list(1,2), "Return");
	print(model_strict$name) #NULL #BEWARE
	... Test continues
})

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request