Lazytest: behavior-driven development/testing framework for Clojure
by Stuart Sierra, http://stuartsierra.com/
Copyright (c) Stuart Sierra, 2010. All rights reserved. The use and distribution terms for this software are covered by the Eclipse Public License 1.0 (http://opensource.org/licenses/eclipse-1.0.php) which can be found in the file LICENSE.html at the root of this distribution. By using this software in any fashion, you are agreeing to be bound by the terms of this license. You must not remove this notice, or any other, from this software.
Use the describe macro to create a group of tests. Start the group
with a documentation string.
(ns examples.readme.groups
(:use [lazytest.describe :only (describe it)]))
(describe "This application" ...)
If you put a symbol before (or instead of) the string, the full name of the Var or Class to which that symbol resolves will be prepended to the doc string:
(describe + "with integers" ...)
;; resulting doc string is "#'clojure.core/+ with integers"
Within a describe group, use the it macro to create a single test
example. Start your example with a documentation string describing
what should happen, followed by an expression to test what you think
should be true.
(describe + "with integers"
(it "computes the sum of 1 and 2"
(= 3 (+ 1 2)))
(it "computes the sum of 3 and 4"
(= 7 (+ 3 4))))
Each it example may only contain one expression, which must return
logical true to indicate the test passed or logical false to indicate
it failed.
Test groups may be nested inside other groups with the testing
macro, which has the same syntax as describe but does not define a
top-level Var:
(ns examples.readme.nested
(:use [lazytest.describe :only (describe it testing)]))
(describe "Addition"
(testing "of integers"
(it "computes small sums"
(= 3 (+ 1 2)))
(it "computes large sums"
(= 7000 (+ 3000 4000))))
(testing "of floats"
(it "computes small sums"
(> 0.00001 (Math/abs (- 0.3 (+ 0.1 0.2)))))
(it "computes large sums"
(> 0.00001 (Math/abs (- 3000.0 (+ 1000.0 2000.0)))))))
Inside a describe or testing group, use the given macro to
define constants shared among several tests:
(ns examples.readme.givens
(:use [lazytest.describe :only (describe it given)]))
(describe "The square root of two"
(given [root (Math/sqrt 2)]
(it "is less than two"
(< root 2))
(it "is more than one"
(> root 1))))
The syntax of given is just like let, including destructuring support.
You can create an example that executes arbitrary code with the
do-it macro. Wrap each assertion expression in the expect macro.
(ns examples.readme.do-it
(:use [lazytest.describe :only (describe do-it)]
[lazytest.expect :only (expect)]))
(describe "Arithmetic"
(do-it "after printing"
(expect (= 4 (+ 2 2)))
(println "Hello, World!")
(expect (= -1 (- 4 5)))))
The expect macro is like assert but carries more information about
the failure. It throws an exception if the expression does not
evaluate to logical true.
If the code inside the do-it macro runs to completion without
throwing an exception, the test example is considered to have passed.
Contexts provide support for executing arbitrary code before, after, or around test cases and test suites.
Fundamentally, a context is a pair of no-argument functions, called
setup and teardown. You can create a context out of two functions
with the fn-context function:
(ns examples.readme.contexts
(:use [lazytest.describe :only (describe testing it with)]
[lazytest.context :only (fn-context)]))
(def my-context
(fn-context (fn [] (println "This happens during setup"))
(fn [] (println "This happens during teardown"))))
A context may be attached (via metadata) to any test case or suite.
To attach contexts to test cases or suites, use the with macro,
which takes a vector of contexts as its first argument. Those
contexts will be attached to each test case or test suite in the body
of with.
(describe "Addition with a context"
(with [my-context]
(it "adds small numbers"
(= 7 (+ 3 4)))
(it "adds large numbers"
(= 7000 (+ 3000 4000)))))
If you want the contexts to be executed only once for a group of
tests, simply wrap the body of the with macro in a single testing
group:
(describe "Addition with a context"
(with [my-context]
(testing "with a nested group"
(it "adds small numbers"
(= 7 (+ 3 4)))
(it "adds large numbers"
(= 7000 (+ 3000 4000))))))
The lazytest.context.stub namespace provides contexts for stubbing
out Vars with alternate definitions.
The lazytest.context.properties namespace provides contexts for
setting Java system properties.
You can create simple contexts that just run some code before or after
tests with the before and after macros. Each takes a body of
expressions to be run during setup or teardown, respectively.
(ns examples.readme.before-after
(use [lazytest.describe :only (describe it with before after)]))
(describe "Addition with a context"
(with [(before (println "This happens before each test"))
(after (println "This happens after each test"))]
(it "adds small numbers"
(= 7 (+ 3 4)))
(it "adds large numbers"
(= 7000 (+ 3000 4000)))))
Contexts which need to provide state information (for example, a database connection or an open file) to their tests are called stateful contexts.
A stateful context has a setup function which returns a value. That
value becomes the "state" of the context and may be retrieved by
calling deref (abbreviated @) on the context.
The teardown function of a stateful context will be called with the current state of the context as its argument.
For example, a stateful context might be used to open and close a database connection:
(ns examples.readme.stateful-contexts
(:use [lazytest.context.stateful :only (stateful-fn-context)]
[lazytest.describe :only (describe using it)]))
(def database-context
(stateful-fn-context
(fn [] ... open & return database connection ...)
(fn [connection] ... close the connection ...)))
(describe "My tests with a database"
(with [database-context]
(it "can read from the database"
... database connection is available as @database-context ...)))
It is also possible to bind a stateful context to a local variable
with the using macro. Like given, the using macro takes a
vector of name-value pairs, but each value must be a stateful context.
Like with, the contexts will be attached to all the tests cases and
or suites within the body of using. The contexts may be
dereferenced by their local names.
(describe "Square root of two with state"
(using [root (stateful-fn-context
(fn [] (Math/sqrt 2))
(fn [x] (println "All done with" x)))]
(it "is less than 2"
(> 2 @root))
(it "is more than 1"
(< 1 @root))))
The lazytest.context.file namespace defines stateful contexts for
creating temporary files and directories.
The describe, testing, it, and do-it macros all take an
optional metadata map immediately after the docstring.
Adding :focus true to this map will cause only that test/suite to
be run. Removing it will return to the normal behavior (run all
tests).
Use random input data in your tests with the for-any macro, which
takes a vector of name-value pairs like given, where each value is a
generator function such as those defined in lazytest.random.
This part needs better documentation.
These instructions require JDK 6.
Put the following in project.clj
(defproject your-project-name "1.0.0-SNAPSHOT"
:description "Your project description"
:dependencies [[org.clojure/clojure "1.2.0"]
[org.clojure/clojure-contrib "1.2.0"]
[com.stuartsierra/lazytest "1.0.1"]]
:repositories {"stuartsierra.com" "http://stuartsierra.com/maven2"})
Put your test sources in test/
Then run:
lein clean
lein deps
java -cp "src:test:classes:lib/*" lazytest.watch src test
And watch your tests run automatically whenever you save a file.
Type CTRL+C to stop.
Put the following in your pom.xml file's <dependencies> section:
<dependency>
<groupId>com.stuartsierra</groupId>
<artifactId>lazytest</artifactId>
<version>1.0.1</version>
</dependency>
And the following in the pom.xml file's <repositories> section:
<repository>
<id>stuartsierra-releases</id>
<url>http://stuartsierra.com/maven2</url>
<releases>
<enabled>true</enabled>
</releases>
<snapshots>
<enabled>false</enabled>
</snapshots>
</repository>
Put your test sources in src/test/clojure/
Then run:
mvn clojure:repl
And type:
(use 'lazytest.watch)
(start ["src"])
And watch your tests run automatically whenever you save a file.
Type CTRL+C to stop.
The smallest unit of testing is a test case, which is a function
(see lazytest.test-case/test-case). When the function is called, it
may throw an exception to indicate failure. If it does not throw an
exception, it is assumed to have passed. The return value of a test
case is always ignored. Running a test case may have side effects.
The macros lazytest.describe/it and lazytest.describe/do-it create
test cases.
Tests cases are organized into suites. A test suite is a function
(see lazytest.suite/suite) that returns a test sequence. A test
sequence (see lazytest.suite/test-seq) is a sequence, possibly lazy,
of test cases and/or test suites. Suites, therefore, may be nested
inside other suites, but nothing may be nested inside a test case.
The macros lazytest.describe/describe and
lazytest.describe/testing create test suites.
A test suite function may NOT have side effects; it is only used to generate test cases and/or other test suites.
A test runnner is responsible for expanding suites (see
lazytest.suite/expand-suite) and running test cases (see
lazytest.test-case/try-test-case). It may also provide feedback on
the success of tests as they run. Two built-in runners are provided,
see lazytest.runner.console/run-tests and
lazytest.runner.debug/run-tests.
The test runner also returns a sequence of results, which are either
suite results (see lazytest.suite/suite-result) or test case
results (see lazytest.test-case/test-case-result). That sequence
of results is passed to a reporter, which formats results for
display to the user. One example reporter is provided, see
lazytest.report.nested/report.
Put the following in .emacs
(eval-after-load 'clojure-mode
'(define-clojure-indent
(describe 'defun)
(testing 'defun)
(given 'defun)
(it 'defun)
(do-it 'defun)))