Čaj - expect(yourTests).to.be("simple");

Čaj enables you to write expectations for your tests in a straightforward and simple way. A typical example is

expect(yourTests).to.be("simple");

There are many comparisons already built into Čaj, e.g.

expect(javasAge).to.be.within(15, 25);

You can also define expectations on collections:

expect(collection).to.include(aSpecificValue);

The parameter collection can be any of the Java standard collections, an array or even a String.

But where Čaj really shines, is its ability to concatenate expectations:

expect(java).to.have.a.property("age").which.is.at.least(20);

5 Minutes Quick Guide

This quick guide will give a brief introduction into Čaj.

The starting point

The starting point of all expectations formulated with Čaj is the method expect() in the Caj class. As this is the only method you will need, it is a good idea to do a single static import:

import static com.netopyr.caj.Caj.expect;

Every expectations starts with a call of the method expect() with the subject of the expectation as the only parameter.

expect(objectUnderTest)

Fill Words

Čaj provides a number of fill words, which can be added anywhere into an expectation. They have no effect on the expectation and their sole purpose is to help you formulate expectations that are easier to read and understand. The following fill words are available:

a, an, and, at, be, been, has, is, of, same, that, to, which, with

Modifiers

Čaj also defines a number of modifiers, which can also be added anywhere into an expectation. But other in contrast to the fill words, modifiers do change the meaning of an expression.

not

The not modifier negates your expectation.

expect(yourTests).not.to.be("hard");

any / all

TBD

length / size

The length or size modifier shift the focus of your expectation to the length or size of the collection, array or String, that was passed into the expect() method. This allows you to formulate expectations like

expect("Hello").to.have.a.length.of.at.most(5);

contain(s) / include(s)

TBD

Finishing an Expectation

The last part of an expectation is a method that specifies what is actually expected. There are numerous methods available, which are explained in the following table .Expectation Methods

Method	Aliases	Description
instanceOf	a, an	Asserts the class of the target value
equal	eq, be	Asserts that the target value is equal to the given value
within		Asserts that a value is within a given range
above	greaterThan, gt	Asserts that a value is above a minimum
least	gte	Asserts that a value is at least as high as a minimum
below	lessThan, lt	Asserts that a value is below a maximum
most	lte	Asserts that a value is at most as high as a maximum
match(es)		Asserts that a String matches a regular expression
length	size, lengthOf, sizeOf	Asserts that a collection, array or String has a certain size resp. length
empty		Asserts that a collection or array is empty
include(s)	contain(s)	Asserts that a collection or array includes the given elements
property		Asserts that an Object has a certain property (optionally with a given value)
string		Asserts that a String contains a given Sub-String
keys		Asserts that a Map contains the given keys
cause(s)		Asserts that calling the Runnable, Callable or Supplier causes the given Throwable
satisfy		Asserts that the value satisfies a given Predicate
closeTo		Asserts that the value is close to a given number (with a given threshold)
members		Asserts that a collection or array contains all of the given elements
change(s)		Asserts that calling the Runnable or Callable will change the given objectproperty
increase(s)		Asserts that calling the Runnable or Callable will increase the given object property
decrease(s)		Asserts that calling the Runnable or Callable will decrease the given object property

Chaining

Expectations can often be chained, which allows you to define several expectations for the same subject in one go.

expect(tea).to.have.property("extras").which.contains("smile");

expect(badFunction).to.cause(Error.class).with.property("message", "testing");

Installation

Čaj is available from JCenter and Maven Central.

To use Čaj in your project, add the following dependency and you are ready to go!

<dependency>
    <groupId>com.netopyr.caj</groupId>
    <artifactId>caj</artifactId>
    <version>0.1.0</version>
    <scope>test</scope>
</dependency>

And here is a small example of a test using Čaj. The example uses TestNG, but you can also use JUnit.

package com.netopyr.caj;

import org.testng.annotations.Test;

import static com.netopyr.caj.Caj.expect;

public class ExampleTests {

    @Test
    public void testsShouldBeSimple() {
        final String yourTest = "simple";

        expect(yourTest).to.be("simple");
    }
}

Further Documentation

• Čaj’s JavaDocs