Modul:ScribuntoUnit

This module provides unit tests for other Lua modules. To test a module, you must create a separate test module, usually located at Module:Module name/testcases. The module is tested with the ScribuntoUnit module, which verifies that the operations defined in the test module produce the expected results.

Test module structure

To make a test module (test suite), start with the following code:

local myModule = require('Module:MyModule') -- the module to be tested
local ScribuntoUnit = require('Module:ScribuntoUnit')
local suite = ScribuntoUnit:new()

After you have done this you can add individual test functions to the suite object. Any function that begins with test is treated as a test. (Other functions will be ignored by ScribuntoUnit, but can be used in the tests themselves.)

function suite:testSomeCall()
    self:assertEquals('expected value', myModule.someCall(123))
    self:assertEquals('other expected value', myModule.someCall(456))
end

function suite:testSomeOtherCall()
    self:assertEquals('expected value', myModule.someOtherCall(123))
    self:assertEquals('other expected value', myModule.someOtherCall(456))
end

The tests you write should make assertions, and ScribuntoUnit will check whether those assertions are true. For example, assertEquals checks that both of the arguments it is given are equal. If ScribuntoUnit doesn't find an assertion to be true, then the test will fail and an error message will be generated. The error message will show which assertion failed verification (other checks on the assertions are not made at this time).

To finish the test module, you need to return the suite object.

return suite

Running the tests

The tests can be run in two ways: through the Lua debug console, and from a wiki page using #invoke. If you are running the tests through the debug console, use the code require('Module:MyModule/testcases').run(). If you are running them from a wiki page, use the code {{#invoke:MyModule/testcases|run}}. This will generate a table containing the results. It is also possible to display a more compact table by using the code {{#invoke:MyModule/testcases|run|displayMode=short}}.

Tests

Error messages

The last parameter of all the test methods is a message that is displayed if validation fails.

self:assertEquals("expected value", myModule.someCall(123), "The call to myModule.someCall(123) didn't return the expected value.")

fail

self:fail(message)

Unconditionally fails a test.

self:fail("Test failed because of X.")

assertTrue, assertFalse

self:assertTrue(expression, message)
self:assertFalse(expression, message)

These test whether the given expression evaluates to true or false. Note that in Lua false and nil evaluate to false, and everything else evaluates to true.

self:assertTrue(2 + 2 == 4)
self:assertTrue('foo')
self:assertFalse(2 + 2 == 5)
self:assertFalse(nil)

assertStringContains

self:assertStringContains(pattern, s, plain, message)

This tests whether pattern is found in the string s. If plain is true, then pattern is interpreted as literal text; otherwise, pattern is interpreted as a ustring pattern.

If the string is not found, the error message shows the values of pattern and s; if s is more than 70 characters long then a truncated version is displayed. This method is useful for testing specific behaviours in complex wikitext.

self:assertStringContains("foo", "foobar") -- passes
self:assertStringContains("foo", "fobar") -- fails
self:assertStringContains(".oo", "foobar") -- passes: matches "foo"
self:assertStringContains(".oo", "foobar", true) -- fails: . is interpreted as a literal character

assertNotStringContains

self:assertNotStringContains(pattern, s, plain, message)

This is the opposite of assertStringContains. The test will fail if pattern is found in the string s. If plain is true, then pattern is interpreted as literal text; otherwise, pattern is interpreted as a ustring pattern.

self:assertNotStringContains("foo", "foobar") -- fails
self:assertNotStringContains("foo", "fobar") -- passes
self:assertNotStringContains(".oo", "foobar") -- fails: matches "foo"
self:assertNotStringContains(".oo", "foobar", true) -- passes: . is interpreted as a literal character

assertEquals

self:assertEquals(expected, actual, message)

This tests whether the first parameter is equal to the second parameter. If both parameters are numbers, the values are instead compared using assertWithinDelta with delta 1e-8 (0.00000001) since numbers are represented as floating points with limited precision.

self:assertEquals(4, calculator.add(2, 2))

assertNotEquals

self:assertNotEquals(expected, actual, message)

This tests whether the first parameter is not equal to the second parameter. If both parameters are numbers, the values are instead compared using assertNotWithinDelta with delta 1e-8 (0.00000001) since numbers are represented as floating points with limited precision.

self:assertNotEquals(5, calculator.add(2, 2))

assertWithinDelta

self:assertWithinDelta(expected, actual, delta, message)

For two numbers, this tests whether the first is within a given distance (delta) from the second. This is useful to compare floating point numbers, which are used to represent numbers in the standard installation of Lua. (To be precise, it uses double-precision floating point numbers.) For example, on the version of Scribunto installed on the English Wikipedia, the expression 0.3 – 0.2 == 0.1 evaluates to false. This is because in practice, the expression 0.3 – 0.2 equals 0.09999999999999997780… and the number 0.1 equals 0.10000000000000000555…. The slight error between the two means that Lua does not consider them equal. Therefore, to test for equality between two floating point numbers, we should accept values within a small distance (delta) of each other, not just equal values. Note that this problem does not affect integers, which can be represented exactly using double-precision floating point numbers up to values of 2^53.

self:assertWithinDelta(0.1, calculator.subtract(0.3, 0.2), 1e-10)

assertNotWithinDelta

self:assertNotWithinDelta(expected, actual, delta, message)

For two numbers, this tests whether the first is not within a given distance (delta) from the second. This test is the inverse of assertWithinDelta.

self:assertNotWithinDelta(0.1, calculator.subtract(0.3, 0.1), 1e-10)

assertDeepEquals

self:assertDeepEquals(expected, actual, message)

This tests whether the first parameter is equal to the second parameter. If the parameters are tables, they are compared recursively, and their __eq metamethods are respected.

self:assertDeepEquals(table1, table2)

assertTemplateEquals

self:assertTemplateEquals(expected, template, args, message)

This tests whether the first parameter equals a template call. The second parameter is the template name, and the third parameter is a table of the template arguments.

self:assertTemplateEquals(4, 'add', {2, 2}) -- true if {{add|2|2}} equals 4

Note that some tags written in XML notation cannot be tested correctly; see the note for the assertResultEquals function below.

assertResultEquals

self:assertResultEquals(expected, text, message)

This tests whether the first parameter equals the expansion of any wikitext. The second parameter can be any wikitext.

self:assertResultEquals(4, '{{#invoke:Calculator|add|2|2}}')

Note that some special tags written in XML notation, such as <pre>, <nowiki>, <gallery> and <ref> cannot be compared correctly. These tags are converted to strip markers before they are processed by Lua. Strip markers are unique, even when generated from identical input, so any tests testing these tags for equality will fail. This also applies to the assertTemplateEquals and assertSameResult functions.

assertSameResult

self:assertSameResult(text1, text2, message)

This tests whether the expansion of a given string of wikitext equals the expansion of another string of wikitext. This can be useful for verifying that a module behaves in the same way as a template it is intended to replace.

self:assertSameResult('{{add|2|2}}', '{{#invoke:Calculator|add|2|2}}')

Note that some tags written in XML notation cannot be tested correctly; see the note for the assertResultEquals function above.

assertThrows

self:assertThrows(fn, expectedMessage, message)

This tests whether a given function throws an exception. If expectedMessage is not nil, it will check that an exception was thrown with the given error message.

-------------------------------------------------------------------------------
-- Unit tests for Scribunto.
-------------------------------------------------------------------------------
require('strict')

local DebugHelper = {}
local ScribuntoUnit = {}

-- The cfg table contains all localisable strings and configuration, to make it
-- easier to port this module to another wiki.
local cfg = mw.loadData('Module:ScribuntoUnit/config')

-------------------------------------------------------------------------------
-- Concatenates keys and values, ideal for displaying a template or parser function argument table.
-- @param keySeparator glue between key and value (defaults to " = ")
-- @param separator glue between different key-value pairs (defaults to ", ")
-- @example concatWithKeys({a = 1, b = 2, c = 3}, ' => ', ', ') => "a => 1, b => 2, c => 3"
-- 
function DebugHelper.concatWithKeys(table, keySeparator, separator)
    keySeparator = keySeparator or ' = '
    separator = separator or ', '
    local concatted = ''
    local i = 1
    local first = true
    local unnamedArguments = true
    for k, v in pairs(table) do
        if first then
            first = false
        else
            concatted = concatted .. separator
        end
        if k == i and unnamedArguments then
            i = i + 1
            concatted = concatted .. tostring(v)
        else
            unnamedArguments = false
            concatted = concatted .. tostring(k) .. keySeparator .. tostring(v)
        end
    end
    return concatted
end

-------------------------------------------------------------------------------
-- Compares two tables recursively (non-table values are handled correctly as well).
-- @param ignoreMetatable if false, t1.__eq is used for the comparison
-- 
function DebugHelper.deepCompare(t1, t2, ignoreMetatable)
    local type1 = type(t1)
    local type2 = type(t2)

    if type1 ~= type2 then 
        return false 
    end
    if type1 ~= 'table' then 
        return t1 == t2 
    end

    local metatable = getmetatable(t1)
    if not ignoreMetatable and metatable and metatable.__eq then 
        return t1 == t2 
    end

    for k1, v1 in pairs(t1) do
        local v2 = t2[k1]
        if v2 == nil or not DebugHelper.deepCompare(v1, v2) then 
            return false 
        end
    end
    for k2, v2 in pairs(t2) do
        if t1[k2] == nil then 
            return false 
        end
    end

    return true
end

-------------------------------------------------------------------------------
-- Raises an error with stack information
-- @param details a table with error details
--        - should have a 'text' key which is the error message to display
--        - a 'trace' key will be added with the stack data
--        - and a 'source' key with file/line number
--        - a metatable will be added for error handling
-- 
function DebugHelper.raise(details, level)
    level = (level or 1) + 1
    details.trace = debug.traceback('', level)
    details.source = string.match(details.trace, '^%s*stack traceback:%s*(%S*: )')

--    setmetatable(details, {
--        __tostring: function() return details.text end
--    })

    error(details, level)
end

-------------------------------------------------------------------------------
-- when used in a test, that test gets ignored, and the skipped count increases by one.
-- 
function ScribuntoUnit:markTestSkipped()
    DebugHelper.raise({ScribuntoUnit = true, skipped = true}, 3)
end

-------------------------------------------------------------------------------
-- Unconditionally fail a test
-- @param message optional description of the test
-- 
function ScribuntoUnit:fail(message)
    DebugHelper.raise({ScribuntoUnit = true, text = "Test failed", message = message}, 2)
end

-------------------------------------------------------------------------------
-- Checks that the input is true
-- @param message optional description of the test
-- 
function ScribuntoUnit:assertTrue(actual, message)
    if not actual then
        DebugHelper.raise({ScribuntoUnit = true, text = string.format("Failed to assert that %s is true", tostring(actual)), message = message}, 2)
    end
end

-------------------------------------------------------------------------------
-- Checks that the input is false
-- @param message optional description of the test
-- 
function ScribuntoUnit:assertFalse(actual, message)
    if actual then
        DebugHelper.raise({ScribuntoUnit = true, text = string.format("Failed to assert that %s is false", tostring(actual)), message = message}, 2)
    end
end

-------------------------------------------------------------------------------
-- Checks an input string contains the expected string
-- @param message optional description of the test
-- @param plain search is made with a plain string instead of a ustring pattern
-- 
function ScribuntoUnit:assertStringContains(pattern, s, plain, message)
	if type(pattern) ~= 'string' then
		DebugHelper.raise({
			ScribuntoUnit = true,
			text = mw.ustring.format("Pattern type error (expected string, got %s)", type(pattern)),
			message = message
		}, 2)
	end
	if type(s) ~= 'string' then
		DebugHelper.raise({
			ScribuntoUnit = true,
			text = mw.ustring.format("String type error (expected string, got %s)", type(s)),
			message = message
		}, 2)
	end
	if not mw.ustring.find(s, pattern, nil, plain) then
		DebugHelper.raise({
			ScribuntoUnit = true,
			text = mw.ustring.format('Failed to find %s "%s" in string "%s"', plain and "plain string" or "pattern", pattern, s),
			message = message
		}, 2)
	end
end

-------------------------------------------------------------------------------
-- Checks an input string doesn't contain the expected string
-- @param message optional description of the test
-- @param plain search is made with a plain string instead of a ustring pattern
-- 
function ScribuntoUnit:assertNotStringContains(pattern, s, plain, message)
	if type(pattern) ~= 'string' then
		DebugHelper.raise({
			ScribuntoUnit = true,
			text = mw.ustring.format("Pattern type error (expected string, got %s)", type(pattern)),
			message = message
		}, 2)
	end
	if type(s) ~= 'string' then
		DebugHelper.raise({
			ScribuntoUnit = true,
			text = mw.ustring.format("String type error (expected string, got %s)", type(s)),
			message = message
		}, 2)
	end
	local i, j = mw.ustring.find(s, pattern, nil, plain)
	if i then
		local match = mw.ustring.sub(s, i, j)
		DebugHelper.raise({
			ScribuntoUnit = true,
			text = mw.ustring.format('Found match "%s" for %s "%s"', match, plain and "plain string" or "pattern", pattern),
			message = message
		}, 2)
	end
end

-------------------------------------------------------------------------------
-- Checks that an input has the expected value.
-- @param message optional description of the test
-- @example assertEquals(4, add(2,2), "2+2 should be 4")
-- 
function ScribuntoUnit:assertEquals(expected, actual, message)
	if type(expected) == 'number' and type(actual) == 'number' then
        self:assertWithinDelta(expected, actual, 1e-8, message)
	elseif expected ~= actual then
        DebugHelper.raise({
            ScribuntoUnit = true, 
            text = string.format("Failed to assert that %s equals expected %s", tostring(actual), tostring(expected)), 
            actual = actual,
            expected = expected,
            message = message,
        }, 2)
    end
end

-------------------------------------------------------------------------------
-- Checks that an input does not have the expected value.
-- @param message optional description of the test
-- @example assertNotEquals(5, add(2,2), "2+2 should not be 5")
-- 
function ScribuntoUnit:assertNotEquals(expected, actual, message)
	if type(expected) == 'number' and type(actual) == 'number' then
        self:assertNotWithinDelta(expected, actual, 1e-8, message)
	elseif expected == actual then
        DebugHelper.raise({
            ScribuntoUnit = true, 
            text = string.format("Failed to assert that %s does not equal expected %s", tostring(actual), tostring(expected)), 
            actual = actual,
            expected = expected,
            message = message,
        }, 2)
    end
end

-------------------------------------------------------------------------------
-- Validates that both the expected and actual values are numbers
-- @param message optional description of the test
-- 
local function validateNumbers(expected, actual, message)
    if type(expected) ~= "number" then
        DebugHelper.raise({
            ScribuntoUnit = true,
            text = string.format("Expected value %s is not a number", tostring(expected)),
            actual = actual,
            expected = expected,
            message = message,
        }, 3)
    end
    if type(actual) ~= "number" then
        DebugHelper.raise({
            ScribuntoUnit = true,
            text = string.format("Actual value %s is not a number", tostring(actual)),
            actual = actual,
            expected = expected,
            message = message,
        }, 3)
    end
end

-------------------------------------------------------------------------------
-- Checks that 'actual' is within 'delta' of 'expected'.
-- @param message optional description of the test
-- @example assertWithinDelta(1/3, 3/9, 0.000001, "3/9 should be 1/3")
function ScribuntoUnit:assertWithinDelta(expected, actual, delta, message)
    validateNumbers(expected, actual, message)
    local diff = expected - actual
    if diff < 0 then diff = - diff end  -- instead of importing math.abs
    if diff > delta then
        DebugHelper.raise({
            ScribuntoUnit = true, 
            text = string.format("Failed to assert that %f is within %f of expected %f", actual, delta, expected), 
            actual = actual,
            expected = expected,
            message = message,
        }, 2)
    end
end

-------------------------------------------------------------------------------
-- Checks that 'actual' is not within 'delta' of 'expected'.
-- @param message optional description of the test
-- @example assertNotWithinDelta(1/3, 2/3, 0.000001, "1/3 should not be 2/3")
function ScribuntoUnit:assertNotWithinDelta(expected, actual, delta, message)
    validateNumbers(expected, actual, message)
    local diff = expected - actual
    if diff < 0 then diff = - diff end  -- instead of importing math.abs
    if diff <= delta then
        DebugHelper.raise({
            ScribuntoUnit = true, 
            text = string.format("Failed to assert that %f is not within %f of expected %f", actual, delta, expected), 
            actual = actual,
            expected = expected,
            message = message,
        }, 2)
    end
end

-------------------------------------------------------------------------------
-- Checks that a table has the expected value (including sub-tables).
-- @param message optional description of the test
-- @example assertDeepEquals({{1,3}, {2,4}}, partition(odd, {1,2,3,4}))
function ScribuntoUnit:assertDeepEquals(expected, actual, message)
    if not DebugHelper.deepCompare(expected, actual) then
        if type(expected) == 'table' then
            expected = mw.dumpObject(expected)
        end
        if type(actual) == 'table' then
            actual = mw.dumpObject(actual)
        end
        DebugHelper.raise({
            ScribuntoUnit = true, 
            text = string.format("Failed to assert that %s equals expected %s", tostring(actual), tostring(expected)), 
            actual = actual,
            expected = expected,
            message = message,
        }, 2)
    end
end

-------------------------------------------------------------------------------
-- Checks that a wikitext gives the expected result after processing.
-- @param message optional description of the test
-- @example assertResultEquals("Hello world", "{{concat|Hello|world}}")
function ScribuntoUnit:assertResultEquals(expected, text, message)
    local frame = self.frame
    local actual = frame:preprocess(text)
    if expected ~= actual then
        DebugHelper.raise({
            ScribuntoUnit = true, 
            text = string.format("Failed to assert that %s equals expected %s after preprocessing", text, tostring(expected)), 
            actual = actual,
            actualRaw = text,
            expected = expected,
            message = message,
        }, 2)
    end
end

-------------------------------------------------------------------------------
-- Checks that two wikitexts give the same result after processing.
-- @param message optional description of the test
-- @example assertSameResult("{{concat|Hello|world}}", "{{deleteLastChar|Hello world!}}")
function ScribuntoUnit:assertSameResult(text1, text2, message)
    local frame = self.frame
    local processed1 = frame:preprocess(text1)
    local processed2 = frame:preprocess(text2)
    if processed1 ~= processed2 then
        DebugHelper.raise({
            ScribuntoUnit = true, 
            text = string.format("Failed to assert that %s equals expected %s after preprocessing", processed1, processed2), 
            actual = processed1,
            actualRaw = text1,
            expected = processed2,
            expectedRaw = text2,
            message = message,
        }, 2)
    end
end

-------------------------------------------------------------------------------
-- Checks that a parser function gives the expected output.
-- @param message optional description of the test
-- @example assertParserFunctionEquals("Hello world", "msg:concat", {"Hello", " world"})
function ScribuntoUnit:assertParserFunctionEquals(expected, pfname, args, message)
    local frame = self.frame
    local actual = frame:callParserFunction{ name = pfname, args = args}
    if expected ~= actual then
        DebugHelper.raise({
            ScribuntoUnit = true, 
            text = string.format("Failed to assert that %s with args %s equals expected %s after preprocessing", 
                                 DebugHelper.concatWithKeys(args), pfname, expected),
            actual = actual,
            actualRaw = pfname,
            expected = expected,
            message = message,
        }, 2)
    end
end

-------------------------------------------------------------------------------
-- Checks that a template gives the expected output.
-- @param message optional description of the test
-- @example assertTemplateEquals("Hello world", "concat", {"Hello", " world"})
function ScribuntoUnit:assertTemplateEquals(expected, template, args, message)
    local frame = self.frame
    local actual = frame:expandTemplate{ title = template, args = args}
    if expected ~= actual then
        DebugHelper.raise({
            ScribuntoUnit = true, 
            text = string.format("Failed to assert that %s with args %s equals expected %s after preprocessing", 
                                 DebugHelper.concatWithKeys(args), template, expected),
            actual = actual,
            actualRaw = template,
            expected = expected,
            message = message,
        }, 2)
    end
end

-------------------------------------------------------------------------------
-- Checks whether a function throws an error
-- @param fn the function to test
-- @param expectedMessage optional the expected error message
-- @param message optional description of the test
function ScribuntoUnit:assertThrows(fn, expectedMessage, message)
    local succeeded, actualMessage = pcall(fn)
    if succeeded then
        DebugHelper.raise({
            ScribuntoUnit = true,
            text = 'Expected exception but none was thrown',
            message = message,
        }, 2)
    end
	-- For strings, strip the line number added to the error message
    actualMessage = type(actualMessage) == 'string' 
    	and string.match(actualMessage, 'Module:[^:]*:[0-9]*: (.*)')
    	or actualMessage
    local messagesMatch = DebugHelper.deepCompare(expectedMessage, actualMessage)
    if expectedMessage and not messagesMatch then
        DebugHelper.raise({
            ScribuntoUnit = true,
            expected = expectedMessage,
            actual = actualMessage,
            text = string.format('Expected exception with message %s, but got message %s', 
                tostring(expectedMessage), tostring(actualMessage)
            ),
            message = message
        }, 2)
    end
end

-------------------------------------------------------------------------------
-- Checks whether a function doesn't throw an error
-- @param fn the function to test
-- @param message optional description of the test
function ScribuntoUnit:assertDoesNotThrow(fn, message)
	local succeeded, actualMessage = pcall(fn)
	if succeeded then
	    return
	end
	-- For strings, strip the line number added to the error message
	actualMessage = type(actualMessage) == 'string' 
		and string.match(actualMessage, 'Module:[^:]*:[0-9]*: (.*)')
		or actualMessage
	DebugHelper.raise({
		ScribuntoUnit = true,
		actual = actualMessage,
		text = string.format('Expected no exception, but got exception with message %s',
			tostring(actualMessage)
		),
		message = message
	}, 2)
end

-------------------------------------------------------------------------------
-- Creates a new test suite.
-- @param o a table with test functions (alternatively, the functions can be added later to the returned suite)
-- 
function ScribuntoUnit:new(o)
    o = o or {}
    o._tests = {}
    setmetatable(o, {
    	__index = self,
    	__newindex = function (t, k, v)
    		if type(k) == "string" and k:find('^test') and type(v) == "function" then
    			-- Store test functions in the order they were defined
    			table.insert(o._tests, {name = k, test = v})
    		else
    			rawset(t, k, v)
    		end
    	end
    })
    o.run = function(frame) return self:run(o, frame) end
    return o
end

-------------------------------------------------------------------------------
-- Resets global counters
-- 
function ScribuntoUnit:init(frame)
    self.frame = frame or mw.getCurrentFrame()
    self.successCount = 0
    self.failureCount = 0
    self.skipCount = 0
    self.results = {}
end

-------------------------------------------------------------------------------
-- Runs a single testcase
-- @param name test nume
-- @param test function containing assertions
-- 
function ScribuntoUnit:runTest(suite, name, test)
    local success, details = pcall(test, suite)
    
    if success then
        self.successCount = self.successCount + 1
        table.insert(self.results, {name = name, success = true})
    elseif type(details) ~= 'table' or not details.ScribuntoUnit then -- a real error, not a failed assertion
        self.failureCount = self.failureCount + 1
        table.insert(self.results, {name = name, error = true, message = 'Lua error -- ' .. tostring(details)})
    elseif details.skipped then
        self.skipCount = self.skipCount + 1
        table.insert(self.results, {name = name, skipped = true})
    else
        self.failureCount = self.failureCount + 1
        local message = details.source or ""
        if details.message then
            message = message .. details.message .. "\n"
        end
        message = message .. details.text
        table.insert(self.results, {name = name, error = true, message = message, expected = details.expected, actual = details.actual, testname = details.message})
    end
end

-------------------------------------------------------------------------------
-- Runs all tests and displays the results.
-- 
function ScribuntoUnit:runSuite(suite, frame)
    self:init(frame)
	for i, testDetails in ipairs(suite._tests) do
		self:runTest(suite, testDetails.name, testDetails.test)
	end
    return {
        successCount = self.successCount,
        failureCount = self.failureCount,
        skipCount = self.skipCount,
        results = self.results,
    }
end

-------------------------------------------------------------------------------
-- #invoke entry point for running the tests.
-- Can be called without a frame, in which case it will use mw.log for output
-- @param displayMode see displayResults()
-- 
function ScribuntoUnit:run(suite, frame)
    local testData = self:runSuite(suite, frame)
    if frame and frame.args then
        return self:displayResults(testData, frame.args.displayMode or 'table')
    else
        return self:displayResults(testData, 'log')
    end
end

-------------------------------------------------------------------------------
-- Displays test results 
-- @param displayMode: 'table', 'log' or 'short'
-- 
function ScribuntoUnit:displayResults(testData, displayMode)
    if displayMode == 'table' then
        return self:displayResultsAsTable(testData)
    elseif displayMode == 'log' then
        return self:displayResultsAsLog(testData)
    elseif displayMode == 'short' then
        return self:displayResultsAsShort(testData)
    else
        error('unknown display mode')
    end
end

function ScribuntoUnit:displayResultsAsLog(testData)
    if testData.failureCount > 0 then
        mw.log('FAILURES!!!')
    elseif testData.skipCount > 0 then
        mw.log('Some tests could not be executed without a frame and have been skipped. Invoke this test suite as a template to run all tests.')
    end
    mw.log(string.format('Assertions: success: %d, error: %d, skipped: %d', testData.successCount, testData.failureCount, testData.skipCount))
    mw.log('-------------------------------------------------------------------------------')
    for _, result in ipairs(testData.results) do
        if result.error then
            mw.log(string.format('%s: %s', result.name, result.message))
        end
    end
end

function ScribuntoUnit:displayResultsAsShort(testData)
    local text = string.format(cfg.shortResultsFormat, testData.successCount, testData.failureCount, testData.skipCount)
    if testData.failureCount > 0 then
        text = '<span class="error">' .. text .. '</span>'
    end
    return text
end

function ScribuntoUnit:displayResultsAsTable(testData)
    local successIcon, failIcon = self.frame:preprocess(cfg.successIndicator), self.frame:preprocess(cfg.failureIndicator)
    local text = ''
	if testData.failureCount > 0 then
		local msg = mw.message.newRawMessage(cfg.failureSummary, testData.failureCount):plain()
		msg = self.frame:preprocess(msg)
		if cfg.failureCategory then
			msg = cfg.failureCategory .. msg
		end
		text = text .. failIcon .. ' ' .. msg .. '\n'
	else
		text = text .. successIcon .. ' ' .. cfg.successSummary .. '\n'
	end
    text = text .. '{| class="wikitable scribunto-test-table"\n'
    text = text .. '!\n! ' .. cfg.nameString .. '\n! ' .. cfg.expectedString .. '\n! ' .. cfg.actualString .. '\n'
    for _, result in ipairs(testData.results) do
        text = text .. '|-\n'
        if result.error then
            text = text .. '| ' .. failIcon .. '\n| '
            if (result.expected and result.actual) then
            	local name = result.name
            	if result.testname then
            		name = name .. ' / ' .. result.testname
            	end
                text = text .. mw.text.nowiki(name) .. '\n| ' .. mw.text.nowiki(tostring(result.expected)) .. '\n| ' .. mw.text.nowiki(tostring(result.actual)) .. '\n'
            else
                text = text .. mw.text.nowiki(result.name) .. '\n| ' .. ' colspan="2" | ' .. mw.text.nowiki(result.message) .. '\n'
            end
        else
            text = text .. '| ' .. successIcon .. '\n| ' .. mw.text.nowiki(result.name) .. '\n|\n|\n'
        end
    end
    text = text .. '|}\n'
    return text
end

return ScribuntoUnit