Customization¶

Since the default Generators may produce values in undesired range, KFixture has some possibilities to deal with that.

Ranges¶

Atomics¶

Let's say you need an integer in the range of 12 to 42. You can set an additional range argument:

class MySpec {
    private val fixture = kotlinFixture()

    @Test
    fun myAwesomeTest() {
        val value: Int = fixture.fixture(
            from = 12,
            to = 42,
        )
        ...
    }
}

Alternatively you can also use a ClosedRange:

class MySpec {
    private val fixture = kotlinFixture()

    @Test
    fun myAwesomeTest() {
        val value: Int = fixture.fixture(
            range = 12..42,
        )
        ...
    }
}

Note

For numbers the default range goes over the entire range of the type. Chars however will be chosen between (32) and ~ (126).

If you want simply to express that you want only positive/negative number, KFixture has a short cut for that:

class MySpec {
    private val fixture = kotlinFixture()

    @Test
    fun myAwesomeTest() {
        val value: Int = fixture.fixture(
            sign = Sign.POSITIVE,
        )
        ...
    }
}

Note

Float does not support signing.

AtomicArrays¶

AtomicArrays (e.g. ByteArray) have similar capacities as Atomics. They can use range arguments:

class MySpec {
    private val fixture = kotlinFixture()

    @Test
    fun myAwesomeTest() {
        val value: IntArray = fixture.fixture(
            from = 12,
            to = 42,
        )
        ...
    }
}

or ClosedRange:

class MySpec {
    private val fixture = kotlinFixture()

    @Test
    fun myAwesomeTest() {
        val value: IntArray = fixture.fixture(
            12..42,
        )
        ...
    }
}

or signing:

class MySpec {
    private val fixture = kotlinFixture()

    @Test
    fun myAwesomeTest() {
        val value: IntArray = fixture.fixture(
            sign = Sign.NEGATIVE,
        )
        ...
    }
}

Additionally AtomicArrays can take multiple ranges. KFixture will randomly select a range per item:

class MySpec {
    private val fixture = kotlinFixture()

    @Test
    fun myAwesomeTest() {
        val value: IntArray = fixture.fixture(
            12..42,
            102..222,
            143..567
        )
        ...
    }
}

Size¶

AtomicArrays and build-in Generics (except Tuples and Enums) are also sizeable. This means they take an additional parameter - size - in order to determine the amount of items:

class MySpec {
    private val fixture = kotlinFixture()

    @Test
    fun myAwesomeTest() {
        val value: IntArray = fixture.fixture(
            size = 23,
        )
        ...
    }
}

Note

If you do not set a size it will randomly choose one (between 1 and 10 items).

Filter¶

In some cases it might be desired to filter certain values out. KFixture provides for this a handle similar to Kotlin's filter. You may simply provide a predicate:

class MySpec {
    private val fixture = kotlinFixture()

    @Test
    fun myAwesomeTest() {
        val value: IntArray = fixture.fixture(
            from = 12,
            to = 42,
        ) { it != 40 } // 40 will be excluded
        ...
    }
}

Nested Generators¶

In order to keep Generics agnostic they will not take a concrete parameter like predicate. However all Generic Generators will allow you to inject a customized Generator via nestedGenerator or similar:

class MySpec {
    private val fixture = kotlinFixture()

    private inline fun <reified T : Number> positiveNumber(
        qualifier: PublicApi.Qualifier?
    ): T = fixture.fixture(
        sign = PublicApi.Sign.POSITIVE
    )

    @Test
    fun myAwesomeTest() {
        val value: List<Int> = fixture.listFixture(
            nestedGenerator = ::positiveNumber
        )
        ...
    }
}

Selections¶

Inline¶

fixture is also capable to pick values from a given Iterable:

class MySpec {
    private val fixture = kotlinFixture()
    private val possibleValues = listOf("a", "b", "c")

    @Test
    fun myAwesomeTest() {
        val value1 = fixture.fixture(possibleValues)
        val value2 = fixture.fixture(0..100)
        ...
    }
}

Selection Generator¶

If you want to distribute options over the entire lifetime of fixture you can use the SelectionGenerator:

class MySpec {
    private val fixture = kotlinFixture {
        useSelector(
            options = listOf("a", "b", "c"),
            qualifier = qualifiedBy("abc")
        )
    }

    @Test
    fun myAwesomeTest() {
        val value: String = fixture.fixture(
            qualifier = qualifiedBy("abc")
        )
        ...
    }
}

The selector will pick a value of the provided option list whenever it is referenced. You also may noticed the usage of a qualifier. Qualifiers are described in under Extensions, so please take a look there.

Overview¶

Atomics¶

Type	Range	Signed	Filterable
Any	❌	❌	❌
Boolean	❌	❌	❌
Byte	✅	✅	✅
Char	✅	❌	✅
Double	✅	✅	✅
Float	✅	❌	✅
Int	✅	✅	✅
Long	✅	✅	✅
Short	✅	✅	✅
Unit	❌	❌	❌
UByte	✅	❌	✅
UInt	✅	❌	✅
ULong	✅	❌	✅
UShort	✅	❌	✅

AtomicArrays¶

Type	Range	Signed	Filterable
BooleanArray	❌	❌	❌
ByteArray	✅	✅	✅
CharArray	✅	❌	✅
String	✅	❌	✅
DoubleArray	✅	✅	✅
FloatArray	✅	❌	✅
IntArray	✅	✅	✅
LongArray	✅	✅	✅
ShortArray	✅	✅	✅
UByteArray	✅	❌	✅
UIntArray	✅	❌	✅
ULongArray	✅	❌	✅
UShortArray	✅	❌	✅