namespace Example.Tests

open Example
open Mutannot
open Xunit

type CalculatorTests() =
    [<Fact>]
    [<MutationCase("calc-add-one", "Example.Tests/Calculator.fs", 4, "value + 1", "value - 1")>]
    member _.AddOne_increments() =
        Assert.Equal(42, Calculator.addOne 41)

    [<Fact>]
    [<MutationCase("calc-abs-diff-branch", "Example.Tests/Calculator.fs", 7, "left - right", "right - left")>]
    member _.AbsoluteDifference_preserves_order() =
        Assert.Equal(7, Calculator.absoluteDifference 10 3)

    [<Fact>]
    [<MutationCase("calc-leap-year-century", "Example.Tests/Calculator.fs", 10, "year % 100 <> 0", "year % 100 = 0")>]
    member _.LeapYear_handles_centuries() =
        Assert.True(Calculator.isLeapYear 2000)
        Assert.False(Calculator.isLeapYear 1900)