feat(#31): add minus operations for AnyInt

changelog.md

@@ -32,7 +32,7 @@ class NotEmptyList<out E> : NotEmptyCollection<E>
 class NotEmptySet<out E> : NotEmptyCollection<E>
 ```
 
-- Binary operations (`plus`) for the `AnyInt` hierarchy (issue
+- Binary operations (`plus`, `minus`) for the `AnyInt` hierarchy (issue
   [#31](https://github.com/kotools/types/issues/31)).
 
 ```kotlin

src/commonMain/kotlin/kotools/types/number/AnyInt.kt

@@ -35,6 +35,18 @@ public operator fun AnyInt.plus(other: Int): Int = toInt() + other
 @SinceKotoolsTypes("4.1")
 public operator fun AnyInt.plus(other: AnyInt): Int = toInt() + other
 
+/** Subtracts the [other] integer from this one. */
+@SinceKotoolsTypes("4.1")
+public operator fun Int.minus(other: AnyInt): Int = this - other.toInt()
+
+/** Subtracts the [other] integer from this one. */
+@SinceKotoolsTypes("4.1")
+public operator fun AnyInt.minus(other: Int): Int = toInt() - other
+
+/** Subtracts the [other] integer from this one. */
+@SinceKotoolsTypes("4.1")
+public operator fun AnyInt.minus(other: AnyInt): Int = toInt() - other
+
 internal sealed interface AnyIntSerializer<I : AnyInt> : KSerializer<I> {
     val serialName: Result<NotBlankString>
 

src/commonTest/kotlin/kotools/types/number/AnyIntTest.kt

@@ -33,6 +33,30 @@ class AnyIntTest {
         val result: Int = x + y
         result shouldEqual x.toInt() + y.toInt()
     }
+
+    @Test
+    fun int_minus_should_pass() {
+        val x: Int = Random.nextInt()
+        val y: AnyInt = NonZeroInt.random()
+        val result: Int = x - y
+        result shouldEqual x - y.toInt()
+    }
+
+    @Test
+    fun minus_should_pass_with_an_Int() {
+        val x: AnyInt = PositiveInt.random()
+        val y: Int = Random.nextInt()
+        val result: Int = x - y
+        result shouldEqual x.toInt() - y
+    }
+
+    @Test
+    fun minus_should_pass_with_an_AnyInt() {
+        val x: AnyInt = PositiveInt.random()
+        val y: AnyInt = NegativeInt.random()
+        val result: Int = x - y
+        result shouldEqual x.toInt() - y.toInt()
+    }
 }
 
 class AnyIntSerializerTest {