Range Sources

The various range sources can be used to provide a series of numeric arguments with fixed differences between them (i.e., arithmetic progressions) to a @ParameterizedTest. There is a range source for every corresponding numeric primitive type: ByteRangeSource, ShortRangeSource, IntRangeSource, LongRangeSource, FloatRangeSource, and DoubleRangeSource.

Basic Use

In the basic use case, using any range source with just the from and to parameters will provide a series of numeric arguments with a difference of 1 between them, beginning at from ending at the last value smaller than to (i.e. excluding to).

@ParameterizedTest
@IntRangeSource(from = 0, to = 10)
// called 10 times with `digit` = 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
void validDigit(int digit) {
    System.out.println(digit + " is a valid digit");
}

Defining the step

The step argument allows controlling the difference between the consecutive values. It can be positive or negative:

@ParameterizedTest
@DoubleRangeSource(from = -0.1, to = -10, step = -0.1)
void howColdIsIt(double d) {
    System.out.println(d + " °C is cold");
    System.out.println(d + " °F is REALLY cold");
    System.out.println(d + " K is too cold to be true");
}

Open and closed range sources

By default, range sources represent ranges that are inclusive of the starting point (the from value), and exclusive of the end point (the to value). This behavior can be controlled by specifying the closed argument:

@ParameterizedTest
@ByteRangeSource(from = 0, to = 0)
void illegalRange(byte arg) {
    // this will fail with an IllegalArgumentException
    // since the range will be empty
}

@ParameterizedTest
@LongRangeSource(from = 0L, to = 0L, closed = true)
void legalRange(long arg) {
    // But this is fine
    assertThat(arg).isEqualTo(0L);
}

Empty ranges

The range sources check whether the range defined by from, to, and step is empty and throws an IllegalArgumentException if it is.

Thread-Safety

This extension is safe to use during parallel test execution.