Luaunit is a unit-testing framework for Lua. It allows you to write test functions and test classes with test methods, combined with setup/teardown functionality. A wide range of assertions are supported.
Luaunit supports several output format, like Junit or TAP, for easier integration into Continuous Integration platforms (Jenkins, Maven, ...) . The integrated command-line options provide a flexible interface to select tests by name or patterns, control output format, set verbosity, ...
LuaUnit works with Lua 5.1 and 5.2 . It is tested on Windows XP and Ubuntu 12.04 (see continuous build results on Travis-CI ) and should work on all platforms supported by lua. It has no other dependency than lua itself.
LuaUnit is packed into a single-file. To make start using it, just add the file to your project.
Luaunit is developed on Github.
Bugs or feature requests must be reported using GitHub issues.
It is released under the BSD license.
This documentation is available at Read-the-docs.
To get started, create your file test_something.lua .
The script should import LuaUnit:
require('luaunit')
The last line executes your script with LuaUnit and exit with the proper error code:
os.exit( LuaUnit.run() )
Now, run your file with:
lua test_something.lua
It prints something like:
Started on 08/07/14 07:07:40
=========================================================
Success: 100% - 0 / 0, executed in 0.000 seconds
Now, your testing framework is in place, you can start writing tests.
LuaUnit scans all variables that start with test or Test. If they are functions, or if they are tables that contain functions that start with test or Test, they are run as part of the test suite.
So just write a function whose name starts with test. Inside test functions, use the assertions functions provided by LuaUnit, such as assertEquals().
Let’s see that in practice.
Suppose you want to test the following add function:
function add(v1,v2)
-- add positive numbers
-- return 0 if any of the numbers are 0
-- error if any of the two numbers are negative
if v1 < 0 or v2 < 0 then
error('Can only add positive or null numbers, received '..v1..' and '..v2)
end
if v1 == 0 or v2 == 0 then
return 0
end
return v1+v2
end
You write the following tests:
function testAddPositive()
assertEquals(add(1,1),2)
end
function testAddZero()
assertEquals(add(1,0),0)
assertEquals(add(0,5),0)
assertEquals(add(0,0),0)
end
assertEquals() is the most common used assertion function. It simply verifies that both argument are equals, in the order actual value, expected value.
Rerun your test script:
lua test_something.lua
It now prints:
Started on 08/16/14 13:55:18
>>>>>>>>> <TestFunctions>
>>> testAddPositive
>>> testAddZero
=========================================================
Success: 100% - 2 / 2, executed in 0.000 seconds
You always have:
You also want to test that when the function receives negative numbers, it generates an error. Use assertError() or even better, assertErrorMsgContains() to also validate the content of the error message. There are other types or error checking functions, see Error assertions . Here we use assertErrorMsgContains() . First argument is the expected message, then the function to call and the optional arguments:
function testAddError()
assertErrorMsgContains('Can only add positive or null numbers, received 2 and -3', add, 2, -3)
end
Now, suppose we also have the following function to test:
function adder(v)
-- return a function that adds v to its argument using add
function closure( x ) return x+v end
return closure
end
We want to test the type of the value returned by adder and its behavior. LuaUnit provides assertion for type testing (see Type assertions). In this case, we use assertIsFunction():
function testAdder()
f = adder(3)
assertIsFunction( f )
assertEquals( f(2), 5 )
end
When the number of tests starts to grow, you usually organise them into separate groups. You can do that with LuaUnit by putting them inside a table (whose name must start with Test or test ).
For example, assume we have a second function to test:
function div(v1,v2)
-- divide positive numbers
-- return 0 if any of the numbers are 0
-- error if any of the two numbers are negative
if v1 < 0 or v2 < 0 then
error('Can only divide positive or null numbers, received '..v1..' and '..v2)
end
if v1 == 0 or v2 == 0 then
return 0
end
return v1/v2
end
We move the tests related to the function add into their own table:
TestAdd = {}
function TestAdd:testAddPositive()
assertEquals(add(1,1),2)
end
function TestAdd:testAddZero()
assertEquals(add(1,0),0)
assertEquals(add(0,5),0)
assertEquals(add(0,0),0)
end
function TestAdd:testAddError()
assertErrorMsgContains('Can only add positive or null numbers, received 2 and -3', add, 2, -3)
end
function TestAdd:testAdder()
f = adder(3)
assertIsFunction( f )
assertEquals( f(2), 5 )
end
-- end of table TestAdd
Then we create a second set of tests for div:
TestDiv = {}
function TestDiv:testDivPositive()
assertEquals(div(4,2),2)
end
function TestDiv:testDivZero()
assertEquals(div(4,0),0)
assertEquals(div(0,5),0)
assertEquals(div(0,0),0)
end
function TestDiv:testDivError()
assertErrorMsgContains('Can only div positive or null numbers, received 2 and -3', div, 2, -3)
end
-- end of table TestDiv
Execution of the test suite now looks like this:
Started on 08/16/14 22:05:03
>>>>>>>>> TestAdd
>>> TestAdd.testAddError
>>> TestAdd.testAddPositive
>>> TestAdd.testAddZero
>>> TestAdd.testAdder
>>>>>>>>> TestDiv
>>> TestDiv.testDivError
>>> TestDiv.testDivPositive
>>> TestDiv.testDivZero
=========================================================
Success: 100% - 7 / 7, executed in 0.000 seconds
When tests are defined in tables, you can optionally define two special functions, setUp() and tearDown(), which will be executed respectively before and after every test.
These function may be used to create specific resources for the test being executed and cleanup the test environment.
For a practical example, imagine that we have a log() function that writes strings to a log file on disk. The file is created upon first usage of the function, and the filename is defined by calling the function initLog().
The tests for these functions would take advantage of the setup/teardown functionality to prepare a log filename shared by all tests, make sure that all tests start with a non existing log file name, and erase the log filename after every test:
TestLogger = {}
function TestLogger:setUp()
-- define the fname to use for logging
self.fname = 'mytmplog.log'
-- make sure the file does not already exists
os.remove(self.fname)
end
function TestLogger:testLoggerCreatesFile()
initLog(self.fname)
log('toto')
-- make sure that our log file was created
f = io.open(self.fname, 'r')
assertNotNil( f )
f:close()
end
function TestLogger:tearDown()
-- cleanup our log file after all tests
os.remove(self.fname)
end
You can control the LuaUnit execution from the command-line:
Output format
Choose the test output format with -o or --output. Available formats are:
Example:
lua my_test_suite.lua -o TAP
List of tests to run
You can list some test names on the command-line to run only those tests. The name must be the exact match of either the test table, the test function or the test table and the test method. The option may be repeated.
Example:
-- Run all TestAdd table tests and one test of TestDiv table.
lua my_test_suite.lua TestAdd TestDiv.testDivError
Filtering tests
The most flexible approach for selecting tests to run is to use a pattern. With --pattern or -p, you can provide a lua pattern and only the tests that contain the pattern will actually be run.
Example:
-- Run all tests of zero testing and error testing
-- by using the magic character .
lua my_test_suite.lua -p Err.r -p Z.ro
For our test suite, it gives the following output:
Started on 08/16/14 22:38:30
>>>>>>>>> TestAdd
>>> TestAdd.testAddError
>>> TestAdd.testAddZero
>>>>>>>>> TestDiv
>>> TestDiv.testDivError
>>> TestDiv.testDivZero
=========================================================
Success: 100% - 4 / 4, executed in 0.000 seconds
The pattern can be any lua pattern. Be sure to exclude all magic characters with % (like -+?*) and protect your pattern from the shell interpretation by putting it in quotes.
You now know enough of LuaUnit to start writing your test suite. Check the reference documentation for a complete list of assertions, command-line options and specific behavior.
Return value
Normally, you should run your test suite with the following line:
os.exit(LuaUnit.run())
The run() function returns the number of failures of the test suite. This is good for an exit code, 0 meaning success.
Arguments
If no arguments are supplied, it parses the command-line arguments of the script and interpret them. If arguments are supplied to the function, they are parsed instead of the command-line. It uses the same syntax.
Example:
-- execute tests matching the 'withXY' pattern
os.exit(LuaUnit.run('--pattern', 'withXY'))
Choice of tests
If test names were supplied, only those tests are executed. When test names are supplied, they don’t have to start with test, they are run anyway.
If no test names were supplied, a general test collection process starts under the following rules:
all variable starting with test or Test are scanned.
if the variable is a function it is collected for testing
if the variable is a table:
- all keys starting with test or Test are collected (provided that they are functions)
- keys with name setUp and tearDown are also collected
If one or more pattern were supplied, the test are then filtered according the pattern(s). Only the test that match the pattern(s) are actually executed.
setup and teardown
The function setUp() is executed before each test if it exists in the table. The function tearDown() is executed after every test if it exists in the table.
Note
tearDown() is always executed if it exists, even if there was a failure in the test or in the setUp() function. Failures in setUp() or tearDown() are considered as a general test failures.
If you want to keep the flexibility of the command-line parsing, but want to force some parameters, like the output format, you must use a slightly different syntax:
lu = LuaUnit.new()
lu:setOutputType("tap")
os.exit( lu:runSuite() )
runSuite() behaves like run() except that it must be started with a LuaUnit instance as first argument, and it will use the LuaUnit instance settings.
Usage: lua <your_test_suite.lua> [options] [testname1 [testname2]
Test names
When no test names are supplied, all tests are collected.
The syntax for supplying test names can be either: name of the function, name of the table or name of the table + ‘.’ + name of the function. Only the supplied tests will be executed.
Selecting output format
Choose the output format with the syntax -o FORMAT or --output FORMAT.
Formats available:
Warning
In the JUnit format, a destination filename must be supplied with --name or -n
Destination filename
When using the JUnit format, the test suites writes an XML file with the test results. The file name is mandatory and must be supplied with: --name FILENAME or -n FILENAME
Selecting tests with patterns
You select a subset of tests by specifying one or more filter patterns, with -p PATTERN or --pattern PATTERN.
The pattern is looked for on the full test name TestTable.testMethod . Only the tests that actually match the pattern are selected. When specifying more than one pattern, they are tried one by one until the name matches (OR combination).
Make sure you esape magic chars like +?-* with % .
Other Options:
You will now find the list of all assertion functions. For all functions, When an assertion fails, the failure message tries to be as informative as possible, by displaying the expectation and value that caused the failure.
All equality assertions functions take two arguments, in the order actual value then expected value. Some people are more familiar with the order expected value then actual value. It is possible to configure LuaUnit to use the opposite order for all equality assertions, by setting up a global variable:
ORDER_ACTUAL_EXPECTED=false
The order only matters for the message that is displayed in case of failures. It does not influence the test itself.
Assert that two values are equal.
For tables, the comparison is a deep comparison :
LuaUnit provides other table-related assertions, see Table assertions
Assert that two values are different. The assertion fails if the two values are identical.
It also uses table deep comparison.
Assert that two floating point numbers are almost equal.
When comparing floating point numbers, strict equality does not work. Computer arithmetic is so that an operation that mathematically yields 1.00000000 might yield 0.999999999999 in lua . That’s why you need an almost equals comparison, where you specify the error margin.
Assert that two floating point numbers are not almost equal.
Assert that a given value compares to true. Lua coercion rules are applied so that values like 0, "", 1.17 all compare to true.
Assert that a given value compares to false. Lua coercion rules are applied so that only nil and false all compare to false.
Assert that a given value is nil .
Assert that a given value is not nil . Lua coercion rules are applied so that values like 0, "", false all validate the assertion.
Assert that two variables are identical. For string, numbers, boolean and for nil, this gives the same result as assertEquals() . For the other types, identity means that the two variables refer to the same object.
Example :
s1='toto'
s2='to'..'to'
t1={1,2}
t2={1,2}
assertIs(s1,s1) -- ok
assertIs(s1,s2) -- ok
assertIs(t1,t1) -- ok
assertIs(t1,t2) -- fail
Assert that two variables are not identical, in the sense that they do not refer to the same value. See assertIs() for more details.
Assertions related to string and patterns.
Assert that a string contains the given substring or pattern.
By default, substring is searched in the string. If useRe is provided and is true, sub is treated as a pattern which is searched inside the string str .
Assert that a string contains the given substring, irrespective of the case.
Not that unlike assertStrcontains(), you can not search for a pattern.
Assert that a string does not contain a given substring or pattern.
By default, substring is searched in the string. If useRe is provided and is true, sub is treated as a pattern which is searched inside the string str .
Assert that a string does not contain the given substring, irrespective of the case.
Not that unlike assertNotStrcontains(), you can not search for a pattern.
Assert that a string matches the full pattern pattern.
If start and final are not provided or are nil, the pattern must match the full string, from start to end. The functions allows to specify the expected start and end position of the pattern in the string.
Error related assertions, to verify error generation and error messages.
Assert that calling functions func with the arguments yields an error. If the function does not yield an error, the assertion fails.
Note that the error message itself is not checked, which means that this function does not distinguish between the legitimate error that you expect and another error that might be triggered by mistake.
The next functions provide a better approach to error testing, by checking explicitly the error message content.
Note
When testing LuaUnit, switching from assertError() to assertErrorMsgEquals() revealed quite a few bugs!
Assert that calling function func will generate exactly the given error message. If the function does not yield an error, or if the error message is not identical, the assertion fails.
Be careful when using this function that error messages usually contain the file name and line number information of where the error was generated. This is usually inconvenient. To ignore the filename and line number information, you can either use a pattern with assertErrorMsgMatches() or simply check for the message containt with assertErrorMsgContains() .
Assert that calling function func will generate an error message containing partialMsg . If the function does not yield an error, or if the expected message is not contained in the error message, the assertion fails.
Assert that calling function func will generate an error message matching expectedPattern . If the function does not yield an error, or if the error message does not match the provided patternm the assertion fails.
Note that matching is done from the start to the end of the error message. Be sure to escape magic all magic characters with % (like -+.?*) .
The following functions all perform type checking on their argument. If the received value is not of the right type, the failure message will contain the expected type, the received type and the received value to help you identify better the problem.
Assert that the argument is a number (integer or float)
Assert that the argument is a string.
Assert that the argument is a table.
Assert that the argument is a boolean.
Assert that the argument is a nil.
Assert that the argument is a function.
Assert that the argument is a userdata.
Assert that the argument is a coroutine (an object with type thread ).
An alias for assertIsCoroutine().
Assert that two tables contain the same items, irrespective of their keys.
This function is practical for example if you want to compare two lists but where items are not in the same order:
assertItemsEquals( {1,2,3}, {3,2,1} ) -- assertion succeeds
The comparison is not recursive on the items: if any of the items are tables, they are compared using table equality (like as in assertEquals() ), where the key matters.
assertItemsEquals( {1,{2,3},4}, {4,{3,2,},1} ) -- assertion fails because {2,3} ~= {3,2}