jvmMain.io.kotest.matchers.stats.matchers.kt Maven / Gradle / Ivy
package io.kotest.matchers.stats
import io.kotest.matchers.Matcher
import io.kotest.matchers.MatcherResult
import io.kotest.matchers.should
import io.kotest.matchers.shouldNot
import java.math.BigDecimal
import java.math.MathContext
import java.math.RoundingMode
import kotlin.math.sqrt
/**
* Asserts that mean of the Collection elements equals to [value] with default
* or specific [precision]. Default precision equals 4 digits after decimal point.
*
* Opposite of [shouldNotHaveMean]
*
* Example:
* ```
*
* val collection = listOf(1, 1, 3)
* val firstMean = BigDecimal("1.66667")
* val secondMean = BigDecimal("1.6667")
*
* collection.shouldHaveMean(firstMean, 5) // Assertion passes
* collection.shouldHaveMean(secondMean) // Assertion passes
*
* collection.shouldHaveMean(firstMean) // Assertion fails
* collection.shouldHaveMean(secondMean, 5) // Assertion fails
* ```
*
* @param value - expected mean value
* @param precision - precision, by default - 4 digits after decimal point
*
*/
fun Collection.shouldHaveMean(value: BigDecimal, precision: Int = 4) = this should haveMean(value, precision)
/**
* Asserts that mean of the Collection elements equals to [value] with default
* or specific [precision]. Default precision equals 4 digits after decimal point.
*
* Opposite of [shouldNotHaveMean]
*
* Example:
* ```
*
* val collection = listOf(1, 1, 3)
* val firstMean = 1.66667
* val secondMean = 1.6667
*
* collection.shouldHaveMean(firstMean, 5) // Assertion passes
* collection.shouldHaveMean(secondMean) // Assertion passes
*
* collection.shouldHaveMean(firstMean) // Assertion fails
* collection.shouldHaveMean(secondMean, 5) // Assertion fails
* ```
*
* @param value - expected mean value
* @param precision - precision, by default - 4 digits after decimal point
*
*/
fun Collection.shouldHaveMean(value: Double, precision: Int = 4) = this should haveMean(value, precision)
/**
* Asserts that mean of the Collection elements doesn't equal to [value] with default
* or specific [precision]. Default precision equals 4 digits after decimal point.
*
* Opposite of [shouldHaveMean]
*
* Example:
* ```
*
* val collection = listOf(1, 1, 3)
* val firstMean = BigDecimal("2.0")
* val secondMean = BigDecimal("1.6666667")
*
* collection.shouldNotHaveMean(firstMean) // Assertion passes
* collection.shouldNotHaveMean(secondMean, 5) // Assertion passes
*
* collection.shouldNotHaveMean(BigDecimal("1.6667")) // Assertion fails
* collection.shouldNotHaveMean(BigDecimal("1.6667"), 4) // Assertion fails
* ```
*
* @param value - not expected mean value
* @param precision - precision, by default - 4 digits after decimal point
*
*/
fun Collection.shouldNotHaveMean(value: BigDecimal, precision: Int = 4) = this shouldNot haveMean(value, precision)
/**
* Asserts that mean of the Collection elements doesn't equal to [value] with default
* or specific [precision]. Default precision equals 4 digits after decimal point.
*
* Opposite of [shouldHaveMean]
*
* Example:
* ```
*
* val collection = listOf(1, 1, 3)
*
* collection.shouldNotHaveMean(2.0) // Assertion passes
* collection.shouldNotHaveMean(1.67, 5) // Assertion passes
*
* collection.shouldNotHaveMean(1.6667) // Assertion fails
* collection.shouldNotHaveMean(1.6667, 4) // Assertion fails
* ```
*
* @param value - not expected mean value
* @param precision - precision, by default - 4 digits after decimal point
*
*/
fun Collection.shouldNotHaveMean(value: Double, precision: Int = 4) = this shouldNot haveMean(value, precision)
/**
* Asserts that variance of the Collection elements equals to [value] with default
* or specific [precision]. Default precision equals 4 digits after decimal point.
*
* Opposite of [shouldNotHaveVariance]
*
* Example:
* ```
*
* val collection = listOf(1, 2, 3)
* val firstVariance = BigDecimal("0.66667")
* val secondVariance = BigDecimal("0.6667")
*
* collection.shouldHaveVariance(firstVariance, 5) // Assertion passes
* collection.shouldHaveVariance(secondVariance) // Assertion passes
*
* collection.shouldHaveVariance(firstVariance) // Assertion fails
* collection.shouldHaveVariance(secondVariance, 5) // Assertion fails
* ```
*
* @param value - expected variance value
* @param precision - precision, by default - 4 digits after decimal point
*
*/
fun Collection.shouldHaveVariance(value: BigDecimal, precision: Int = 4) = this should haveVariance(value, precision)
/**
* Asserts that variance of the Collection elements equals to [value] with default
* or specific [precision]. Default precision equals 4 digits after decimal point.
*
* Opposite of [shouldNotHaveVariance]
*
* Example:
* ```
*
* val collection = listOf(1, 2, 3)
*
* collection.shouldHaveVariance(0.66667, 5) // Assertion passes
* collection.shouldHaveVariance(0.6667) // Assertion passes
*
* collection.shouldHaveVariance(0.67) // Assertion fails
* collection.shouldHaveVariance(0.6667, 5) // Assertion fails
* ```
*
* @param value - expected variance value
* @param precision - precision, by default - 4 digits after decimal point
*
*/
fun Collection.shouldHaveVariance(value: Double, precision: Int = 4) = this should haveVariance(value, precision)
/**
* Asserts that variance of the Collection elements doesn't equal to [value] with default
* or specific [precision]. Default precision equals 4 digits after decimal point.
*
* Opposite of [shouldHaveVariance]
*
* Example:
* ```
*
* val collection = listOf(1, 2, 3)
*
* collection.shouldNotHaveVariance(BigDecimal("1.01"), 5) // Assertion passes
* collection.shouldNotHaveVariance(BigDecimal("0.666667")) // Assertion passes
*
* collection.shouldNotHaveVariance(BigDecimal("0.6667")) // Assertion fails
* collection.shouldNotHaveVariance(BigDecimal("0.66667"), 5) // Assertion fails
* ```
*
* @param value - not expected variance value
* @param precision - precision, by default - 4 digits after decimal point
*
*/
fun Collection.shouldNotHaveVariance(value: BigDecimal, precision: Int = 4) = this shouldNot haveVariance(value, precision)
/**
* Asserts that variance of the Collection elements doesn't equal to [value] with default
* or specific [precision]. Default precision equals 4 digits after decimal point.
*
* Opposite of [shouldHaveVariance]
*
* Example:
* ```
*
* val collection = listOf(1, 2, 3)
*
* collection.shouldNotHaveVariance(1.01, 5) // Assertion passes
* collection.shouldNotHaveVariance(0.666667) // Assertion passes
*
* collection.shouldNotHaveVariance(0.6667) // Assertion fails
* collection.shouldNotHaveVariance(0.66667, 5) // Assertion fails
* ```
*
* @param value - not expected variance value
* @param precision - precision, by default - 4 digits after decimal point
*
*/
fun Collection.shouldNotHaveVariance(value: Double, precision: Int = 4) = this shouldNot haveVariance(value, precision)
/**
* Asserts that standard deviation of the Collection elements equals to [value] with default
* or specific [precision]. Default precision equals 4 digits after decimal point.
*
* Opposite of [shouldNotHaveStandardDeviation]
*
* Example:
* ```
*
* val collection = listOf(1, 2, 3)
*
* collection.shouldHaveStandardDeviation(BigDecimal("0.82"), 2) // Assertion passes
* collection.shouldHaveStandardDeviation(BigDecimal("0.8165")) // Assertion passes
*
* collection.shouldHaveStandardDeviation(BigDecimal("0.82")) // Assertion fails
* collection.shouldHaveStandardDeviation(BigDecimal("0.8165"), 5) // Assertion fails
* ```
*
* @param value - expected standard deviation value
* @param precision - precision, by default - 4 digits after decimal point
*
*/
fun Collection.shouldHaveStandardDeviation(value: BigDecimal, precision: Int = 4) = this should haveStandardDeviation(value, precision)
/**
* Asserts that standard deviation of the Collection elements equals to [value] with default
* or specific [precision]. Default precision equals 4 digits after decimal point.
*
* Opposite of [shouldNotHaveStandardDeviation]
*
* Example:
* ```
*
* val collection = listOf(1, 2, 3)
*
* collection.shouldHaveStandardDeviation(0.82, 2) // Assertion passes
* collection.shouldHaveStandardDeviation(0.8165) // Assertion passes
*
* collection.shouldHaveStandardDeviation(0.82) // Assertion fails
* collection.shouldHaveStandardDeviation(0.8165, 5) // Assertion fails
* ```
*
* @param value - expected standard deviation value
* @param precision - precision, by default - 4 digits after decimal point
*
*/
fun Collection.shouldHaveStandardDeviation(value: Double, precision: Int = 4) = this should haveStandardDeviation(value, precision)
/**
* Asserts that standard deviation of the Collection elements doesn't equal to [value] with default
* or specific [precision]. Default precision equals 4 digits after decimal point.
*
* Opposite of [shouldHaveStandardDeviation]
*
* Example:
* ```
*
* val collection = listOf(1, 2, 3)
*
* collection.shouldNotHaveStandardDeviation(BigDecimal("0.8165"), 5) // Assertion passes
* collection.shouldNotHaveStandardDeviation(BigDecimal("0.8333")) // Assertion passes
*
* collection.shouldNotHaveStandardDeviation(BigDecimal("0.8165")) // Assertion fails
* collection.shouldNotHaveStandardDeviation(BigDecimal("0.82"), 2) // Assertion fails
* ```
*
* @param value - not expected standard deviation value
* @param precision - precision, by default - 4 digits after decimal point
*
*/
fun Collection.shouldNotHaveStandardDeviation(value: BigDecimal, precision: Int = 4) = this shouldNot haveStandardDeviation(value, precision)
/**
* Asserts that standard deviation of the Collection elements doesn't equal to [value] with default
* or specific [precision]. Default precision equals 4 digits after decimal point.
*
* Opposite of [shouldHaveStandardDeviation]
*
* Example:
* ```
*
* val collection = listOf(1, 2, 3)
*
* collection.shouldNotHaveStandardDeviation(0.8165, 5) // Assertion passes
* collection.shouldNotHaveStandardDeviation(0.8333) // Assertion passes
*
* collection.shouldNotHaveStandardDeviation(0.8165) // Assertion fails
* collection.shouldNotHaveStandardDeviation(0.82, 2) // Assertion fails
* ```
*
* @param value - not expected standard deviation value
* @param precision - precision, by default - 4 digits after decimal point
*
*/
fun Collection.shouldNotHaveStandardDeviation(value: Double, precision: Int = 4) = this shouldNot haveStandardDeviation(value, precision)
private val defaultMathContext = MathContext(64, RoundingMode.HALF_UP)
private fun BigDecimal.round(precision: Int): BigDecimal = this.setScale(precision, RoundingMode.HALF_UP).stripTrailingZeros()
private fun calculateMean(collection: Collection): BigDecimal {
var sum: BigDecimal = BigDecimal.ZERO
for (elem in collection) {
sum += BigDecimal(elem.toString())
}
return sum.divide(BigDecimal(collection.size), defaultMathContext)
}
private fun calculateVariance(collection: Collection): BigDecimal {
val mean: BigDecimal = calculateMean(collection)
var sumOfSquaredDifferences: BigDecimal = BigDecimal.ZERO
for (elem in collection) {
sumOfSquaredDifferences += (BigDecimal(elem.toString()) - mean).pow(2)
}
return sumOfSquaredDifferences.divide(BigDecimal(collection.size), defaultMathContext)
}
private fun calculateStandardDeviation(collection: Collection): BigDecimal {
val variance = calculateVariance(collection)
val two = BigDecimal(2)
var x0 = BigDecimal.ZERO
var x1 = BigDecimal(sqrt(variance.toDouble()))
while (x0 != x1) {
x0 = x1
x1 = variance.divide(x0, defaultMathContext)
x1 = x1.add(x0)
x1 = x1.divide(two, defaultMathContext)
}
return x1
}
private fun testMean(collection: Collection, expectedValue: BigDecimal, precision: Int): MatcherResult {
val expected = expectedValue.stripTrailingZeros()
val actual = if (collection.isEmpty()) BigDecimal.ZERO else calculateMean(collection).round(precision)
return MatcherResult(
expected.compareTo(actual) == 0,
{ "Collection should have mean $expected but was $actual" },
{
"Collection should not have mean $expected but was $actual"
})
}
private fun testVariance(
collection: Collection,
expectedValue: BigDecimal,
precision: Int
): MatcherResult {
val expected = expectedValue.stripTrailingZeros()
val actual = if (collection.isEmpty()) BigDecimal.ZERO else calculateVariance(collection).round(precision)
return MatcherResult(
expected.compareTo(actual) == 0,
{ "Collection should have variance $expected but was $actual" },
{
"Collection should not have variance $expected but was $actual"
})
}
private fun testStandardDeviation(
collection: Collection,
expectedValue: BigDecimal,
precision: Int
): MatcherResult {
val expected = expectedValue.stripTrailingZeros()
val actual = if (collection.isEmpty()) BigDecimal.ZERO else calculateStandardDeviation(collection).round(precision)
return MatcherResult(
expected.compareTo(actual) == 0,
{ "Collection should have standard deviation $expected but was $actual" },
{
"Collection should not have standard deviation $expected but was $actual"
})
}
fun haveMean(expectedValue: BigDecimal, precision: Int = 4) = object :
Matcher> {
override fun test(value: Collection): MatcherResult = testMean(value, expectedValue, precision)
}
fun haveMean(expectedValue: Double, precision: Int = 4) = object : Matcher> {
override fun test(value: Collection): MatcherResult = testMean(value, expectedValue.toBigDecimal(), precision)
}
fun haveVariance(expectedValue: BigDecimal, precision: Int) = object : Matcher> {
override fun test(value: Collection): MatcherResult = testVariance(value, expectedValue, precision)
}
fun haveVariance(expectedValue: Double, precision: Int) = object : Matcher> {
override fun test(value: Collection): MatcherResult = testVariance(value, expectedValue.toBigDecimal(), precision)
}
fun haveStandardDeviation(expectedValue: BigDecimal, precision: Int) = object : Matcher> {
override fun test(value: Collection): MatcherResult = testStandardDeviation(value, expectedValue, precision)
}
fun haveStandardDeviation(expectedValue: Double, precision: Int) = object : Matcher> {
override fun test(value: Collection): MatcherResult = testStandardDeviation(value, expectedValue.toBigDecimal(), precision)
}
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