Introduction

Expect.kt is a set of assertions that allow you to assert the outcome of testing state using a more fluent and specific set of assertions than you get from the kotlin.test. Each type has a set of extension functions that allow you to check certain specifics that relate to that type.

Rather than fulfilling a specific need this project was started as a means to understand the Kotlin language and explore its features (and limitations). As it stands most of the assertions are not making good use of the "Kotlin way" and are shamelessly ripped off FluentAssertions for .NET. The tweaking and improving come next plus there are actually some really nice bits of testing code with Kotlin.

Syntax

Expect.kt allows you to use two different approaches to defining an assertion.

Expect Syntax

Expect syntax offers typical expect(something).toBeInACertainState style of grammar. The following test highlight this appraoch.

expect("james").toBe("james")

Fluent Syntax

It is also possible to use a more fluent syntax to make the same assertion

"james".should.be("james")

Chaining

Expect.kt allows you to chain assertions to keep things really neat and tidy.

expect("james").toStartWith("j").and.toEndWith("s")

Or, in fluent syntax

"james".should.startWith("j").and.endWith("s")

Standard Assertions

There are a few assertions that can be used against any type,

toBe(...)/be(...)

Assert that the state is the value passed in,

expect("james").toBe("james")
"james".should.be("james")

toNotBe(...)/notBe(...)

Assert that the state is NOT the value passed in,

expect("james").toNotBe("henry")
"james".should.notBe("henry")

toBeNull()/beNull()

Assert that the state is null,

expect(null).toBeNull()
null.should.beNull()

toNotBeNull()/notBeNull()

Assert that the state is NOT null

expect("james").toNotBeNull()
"james".should.notBeNull()

Logic Assertions

toBeTrue()/beTrue()

Assert that the value is true

expect(true).toBeTrue()
true.should.beTrue()

toNotBeTrue()/notBeTrue()

Assert that the state is NOT true

expect(false).toNotBeTrue()
false.should.notBeTrue()

toBeFalse()/beFalse()

Assert that the value is false

expect(false).toBeFalse()
false.should.beFalse()

toNotBeFalse()/notBeFalse()

Assert that the state is NOT false

expect(true).toNotBeFalse()
true.should.notBeFalse()

String Assertions

toBeEmpty

Assert that a string is empty ("").

expect("").toBeEmpty()
"".should.beEmpty()

toNotBeEmpty

Assert that a string is not empty ("").

expect("  ").toNotBeEmpty()
"  ".should.beNotEmpty()

toHaveLength

Assert that a string is of a certain length.

expect("james").toHaveLength(5)
"james".should.haveLength(5)

toBeBlank

Assert that a string is blank, in that it is empty or contains only whitespace.

expect("   ").toBeBlank()
"    ".should.beBlank()

toNotBeBlank

Assert that a string is not blank, in that it isn't empty or contains more than whitespace.

expect("james").toNotBeBlank()
"james".should.notBeBlank()

toBeEquivalentTo

Assert that a string is equal to another string regardless of case.

expect("JAMES").toBeEquivalentTo("james")
"JAMES".should.beEquivalentTo("james")

toEndWith

Assert that a string ends with another string

expect("James").toEndWith("es")
"James".should.endWith("es")

toEndWithEquivalent

Assert that a string ends with another string regardless of case.

expect("JAMES").toEndWithEquivalent("es")
"JAMES".should.endWithEquivalent("es")

toContain

Assert that a string contains another string.

expect("JAMES").toContain("AM")
"JAMES".should.contain("AM)

toContainEquivalent

Assert that a string contains another string regardless of case.

toNotContain

Assert that a string doesn't contain another string.

toNotContainEquivalent

Assert that a string doesn't contain another string regardless of case.

toStartWith

Assert that a string starts with another string.

toStartWithEquivalent

Assert that a string starts with another string regardless of case.

toMatch

Assert that a string matches the given regex.

Numeric Assertions (currently Int, Long, Double)

toBeGreaterOrEqualTo

Assert that a number is greater than or equal to another

toBeGreaterThan

Assert that a number is greater than to another

toBeLessOrEqualTo

Assert that a number is less than or equal to another

toBeLessThan

Assert that a number is less than to another

toBeInRange

Assert that a number is within the lower and upper bounds passed in

toBeApproximately

Assert that a number is approximately another, the level of error is defined by the tolerance value (+/- tolerance)