babashka.impl.clojure.test — borkdude/babashka 0.0.68

A unit testing framework.

ASSERTIONS

The core of the library is the "is" macro, which lets you make assertions of any arbitrary expression:

(is (= 4 (+ 2 2))) (is (instance? Integer 256)) (is (.startsWith "abcde" "ab"))

You can type an "is" expression directly at the REPL, which will print a message if it fails.

user> (is (= 5 (+ 2 2)))

FAIL in  (:1)
expected: (= 5 (+ 2 2))
  actual: (not (= 5 4))
false

The "expected:" line shows you the original expression, and the "actual:" shows you what actually happened. In this case, it shows that (+ 2 2) returned 4, which is not = to 5. Finally, the "false" on the last line is the value returned from the expression. The "is" macro always returns the result of the inner expression.

There are two special assertions for testing exceptions. The "(is (thrown? c ...))" form tests if an exception of class c is thrown:

(is (thrown? ArithmeticException (/ 1 0)))

"(is (thrown-with-msg? c re ...))" does the same thing and also tests that the message on the exception matches the regular expression re:

(is (thrown-with-msg? ArithmeticException #"Divide by zero" (/ 1 0)))

DOCUMENTING TESTS

"is" takes an optional second argument, a string describing the assertion. This message will be included in the error report.

(is (= 5 (+ 2 2)) "Crazy arithmetic")

In addition, you can document groups of assertions with the "testing" macro, which takes a string followed by any number of assertions. The string will be included in failure reports. Calls to "testing" may be nested, and all of the strings will be joined together with spaces in the final report, in a style similar to RSpec http://rspec.info/

(testing "Arithmetic" (testing "with positive integers" (is (= 4 (+ 2 2))) (is (= 7 (+ 3 4)))) (testing "with negative integers" (is (= -4 (+ -2 -2))) (is (= -1 (+ 3 -4)))))

Note that, unlike RSpec, the "testing" macro may only be used INSIDE a "deftest" or "with-test" form (see below).

DEFINING TESTS

There are two ways to define tests. The "with-test" macro takes a defn or def form as its first argument, followed by any number of assertions. The tests will be stored as metadata on the definition.

(with-test (defn my-function [x y] (+ x y)) (is (= 4 (my-function 2 2))) (is (= 7 (my-function 3 4))))

As of Clojure SVN rev. 1221, this does not work with defmacro. See http://code.google.com/p/clojure/issues/detail?id=51

The other way lets you define tests separately from the rest of your code, even in a different namespace:

(deftest addition (is (= 4 (+ 2 2))) (is (= 7 (+ 3 4))))

(deftest subtraction (is (= 1 (- 4 3))) (is (= 3 (- 7 4))))

This creates functions named "addition" and "subtraction", which can be called like any other function. Therefore, tests can be grouped and composed, in a style similar to the test framework in Peter Seibel's "Practical Common Lisp" http://www.gigamonkeys.com/book/practical-building-a-unit-test-framework.html

(deftest arithmetic (addition) (subtraction))

The names of the nested tests will be joined in a list, like "(arithmetic addition)", in failure reports. You can use nested tests to set up a context shared by several tests.

RUNNING TESTS

Run tests with the function "(run-tests namespaces...)":

(run-tests 'your.namespace 'some.other.namespace)

If you don't specify any namespaces, the current namespace is used. To run all tests in all namespaces, use "(run-all-tests)".

By default, these functions will search for all tests defined in a namespace and run them in an undefined order. However, if you are composing tests, as in the "arithmetic" example above, you probably do not want the "addition" and "subtraction" tests run separately. In that case, you must define a special function named "test-ns-hook" that runs your tests in the correct order:

(defn test-ns-hook [] (arithmetic))

Note: test-ns-hook prevents execution of fixtures (see below).

OMITTING TESTS FROM PRODUCTION CODE

You can bind the variable "load-tests" to false when loading or compiling code in production. This will prevent any tests from being created by "with-test" or "deftest".

FIXTURES

Fixtures allow you to run code before and after tests, to set up the context in which tests should be run.

A fixture is just a function that calls another function passed as an argument. It looks like this:

(defn my-fixture [f] Perform setup, establish bindings, whatever. (f) Then call the function we were passed. Tear-down / clean-up code here. )

Fixtures are attached to namespaces in one of two ways. "each" fixtures are run repeatedly, once for each test function created with "deftest" or "with-test". "each" fixtures are useful for establishing a consistent before/after state for each test, like clearing out database tables.

"each" fixtures can be attached to the current namespace like this: (use-fixtures :each fixture1 fixture2 ...) The fixture1, fixture2 are just functions like the example above. They can also be anonymous functions, like this: (use-fixtures :each (fn [f] setup... (f) cleanup...))

The other kind of fixture, a "once" fixture, is only run once, around ALL the tests in the namespace. "once" fixtures are useful for tasks that only need to be performed once, like establishing database connections, or for time-consuming tasks.

Attach "once" fixtures to the current namespace like this: (use-fixtures :once fixture1 fixture2 ...)

Note: Fixtures and test-ns-hook are mutually incompatible. If you are using test-ns-hook, fixture functions will never be run.

SAVING TEST OUTPUT TO A FILE

All the test reporting functions write to the var test-out. By default, this is the same as out, but you can rebind it to any PrintWriter. For example, it could be a file opened with clojure.java.io/writer.

EXTENDING TEST-IS (ADVANCED)

You can extend the behavior of the "is" macro by defining new methods for the "assert-expr" multimethod. These methods are called during expansion of the "is" macro, so they should return quoted forms to be evaluated.

You can plug in your own test-reporting framework by rebinding the "report" function: (report event)

The 'event' argument is a map. It will always have a :type key, whose value will be a keyword signaling the type of event being reported. Standard events with :type value of :pass, :fail, and :error are called when an assertion passes, fails, and throws an exception, respectively. In that case, the event will also have the following keys:

:expected The form that was expected to be true :actual A form representing what actually occurred :message The string message given as an argument to 'is'

The "testing" strings will be a list in "testing-contexts", and the vars being tested will be a list in "testing-vars".

Your "report" function should wrap any printing calls in the "with-test-out" macro, which rebinds out to the current value of test-out.

For additional event types, see the examples in the code.

are clj macro

(are argv expr & args)

Checks multiple assertions with a template expression. See clojure.template/do-template for an explanation of templates.

Example: (are [x y] (= x y) 2 (+ 1 1) 4 (* 2 2)) Expands to: (do (is (= 2 (+ 1 1))) (is (= 4 (* 2 2))))

Note: This breaks some reporting features, such as line numbers.

assert-any clj

(assert-any msg form)

Returns generic assertion code for any test, including macros, Java method calls, or isolated symbols.

assert-expr clj multimethod

assert-predicate clj

(assert-predicate msg form)

Returns generic assertion code for any functional predicate. The 'expected' argument to 'report' will contains the original form, the 'actual' argument will contain the form with all its sub-forms evaluated. If the predicate returns false, the 'actual' form will be wrapped in (not...).

compose-fixtures clj

(compose-fixtures f1 f2)

Composes two fixture functions, creating a new fixture function that combines their behavior.

deftest clj macro

(deftest name & body)

Defines a test function with no arguments. Test functions may call other tests, so tests may be composed. If you compose tests, you should also define a function named test-ns-hook; run-tests will call test-ns-hook instead of testing all vars.

Note: Actually, the test body goes in the :test metadata on the var, and the real function (the value of the var) calls test-var on itself.

When load-tests is false, deftest is ignored.

deftest- clj macro

(deftest- name & body)

Like deftest but creates a private var.

do-report clj

(do-report m)

Add file and line information to a test result and call report. If you are writing a custom assert-expr method, call this function to pass test results to report.

file-position clj deprecated

(file-position n)

Returns a vector [filename line-number] for the nth call up the stack.

Deprecated in 1.2: The information needed for test reporting is now on :file and :line keys in the result map.

function? clj

(function? x)

Returns true if argument is a function or a symbol that resolves to a function (not a macro).

inc-report-counter clj

(inc-report-counter name)

Increments the named counter in report-counters, a ref to a map. Does nothing if report-counters is nil.

initial-report-counters clj

is clj macro

(is form)

(is form msg)

Generic assertion macro. 'form' is any predicate test. 'msg' is an optional message to attach to the assertion.

Example: (is (= 4 (+ 2 2)) "Two plus two should be 4")

Special forms:

(is (thrown? c body)) checks that an instance of c is thrown from body, fails if not; then returns the thing thrown.

(is (thrown-with-msg? c re body)) checks that an instance of c is thrown AND that the message on the exception matches (with re-find) the regular expression re.

join-fixtures clj

(join-fixtures fixtures)

Composes a collection of fixtures, in order. Always returns a valid fixture function, even if the collection is empty.

load-tests clj

True by default. If set to false, no test functions will be created by deftest, set-test, or with-test. Use this to omit tests when compiling or loading production code.

report clj multimethod

Generic reporting function, may be overridden to plug in different report formats (e.g., TAP, JUnit). Assertions such as 'is' call 'report' to indicate results. The argument given to 'report' will be a map with a :type key. See the documentation at the top of test_is.clj for more information on the types of arguments for 'report'.

report-counters clj

run-all-tests clj

(run-all-tests ctx)

(run-all-tests ctx re)

Runs all tests in all namespaces; prints results. Optional argument is a regular expression; only namespaces with names matching the regular expression (with re-matches) will be tested.

run-tests clj

(run-tests ctx)

(run-tests ctx & namespaces)

Runs all tests in the given namespaces; prints results. Defaults to current namespace if none given. Returns a map summarizing test results.

set-test clj macro

(set-test name & body)

Experimental. Sets :test metadata of the named var to a fn with the given body. The var must already exist. Does not modify the value of the var.

When load-tests is false, set-test is ignored.

stack-trace-depth clj

The maximum depth of stack traces to print when an Exception is thrown during a test. Defaults to nil, which means print the complete stack trace.

successful? clj

(successful? summary)

Returns true if the given test summary indicates all tests were successful, false otherwise.

test-all-vars clj

(test-all-vars ctx ns)

Calls test-vars on every var interned in the namespace, with fixtures.

test-ns clj

(test-ns ctx ns)

If the namespace defines a function named test-ns-hook, calls that. Otherwise, calls test-all-vars on the namespace. 'ns' is a namespace object or a symbol.

Internally binds report-counters to a ref initialized to initial-report-counters. Returns the final, dereferenced state of report-counters.

test-out clj

test-var clj

(test-var v)

If v has a function in its :test metadata, calls that function, with testing-vars bound to (conj testing-vars v).

test-vars clj

(test-vars vars)

Groups vars by their namespace and runs test-vars on them with appropriate fixtures applied.

testing clj macro

(testing string & body)

Adds a new string to the list of testing contexts. May be nested, but must occur inside a test function (deftest).

testing-contexts clj

testing-contexts-str clj

(testing-contexts-str)

Returns a string representation of the current test context. Joins strings in testing-contexts with spaces.

testing-vars clj

testing-vars-str clj

(testing-vars-str m)

Returns a string representation of the current test. Renders names in testing-vars as a list, then the source file and line of current assertion.

try-expr clj macro

(try-expr msg form)

Used by the 'is' macro to catch unexpected exceptions. You don't call this.

use-fixtures clj multimethod

Wrap test runs in a fixture function to perform setup and teardown. Using a fixture-type of :each wraps every test individually, while :once wraps the whole run in a single function.

with-test clj macro

(with-test definition & body)

Takes any definition form (that returns a Var) as the first argument. Remaining body goes in the :test metadata function for that Var.

When load-tests is false, only evaluates the definition, ignoring the tests.

with-test-out-internal clj macro

(with-test-out-internal & body)

Runs body with out bound to the value of test-out.