Merge Feature/29 currency unit tests

core/entities/src/commonMain/kotlin/business/Currency.kt

@@ -78,6 +78,12 @@ interface Currency: Comparable<Currency> {
                 decimalPlaces = 2,
                 centsPerUnit = 1,
             )
+
+            /*
+            TODO: Add currencies as different areas are supported by the application
+            1. currency conversion service will be needed; can't use comparable directly
+            2. currency exchange rates will be needed
+             */
         }
     }
 }
@@ -86,8 +92,17 @@ internal class SimpleCurrency(
     override val form: Currency.Form,
 ): Currency {
     override fun compareTo(other: Currency): Int {
-        val otherValue = other.amount * form.centsPerUnit / other.form.centsPerUnit
-        return amount.compareTo(otherValue)
+        when {
+            form.centsPerUnit > other.form.centsPerUnit -> {
+                val thisValue = amount * form.centsPerUnit / other.form.centsPerUnit
+                return thisValue.compareTo(other.amount)
+            }
+            form.centsPerUnit < other.form.centsPerUnit -> {
+                val otherValue = other.amount * other.form.centsPerUnit / form.centsPerUnit
+                return amount.compareTo(otherValue)
+            }
+            else -> return amount.compareTo(other.amount)
+        }
     }
 
     override fun toString(): String {
@@ -98,4 +113,5 @@ fun Currency(amount: Long, form: Currency.Form): Currency {
     return SimpleCurrency(amount, form)
 }
 
+fun Long.dollars() = Currency(this, Currency.Form.usDollars)
 fun Long.dollarCents() = Currency(this, Currency.Form.usDollarCents)

core/entities/src/commonTest/kotlin/org.pointyware.xyz.core.entities/business/CurrencyUnitTest.kt

@@ -0,0 +1,102 @@
+/*
+ * Copyright (c) 2024 Pointyware. Use of this software is governed by the GPL-3.0 license.
+ */
+
+package org.pointyware.xyz.core.entities.business
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+/**
+ *
+ */
+class CurrencyUnitTest {
+
+    data class FormattingCase(
+        val amount: Long,
+        val form: Currency.Form,
+        val expected: String
+    )
+
+    @Test
+    fun testSimpleForm() {
+        listOf(
+            FormattingCase(
+                100,
+                Currency.Form.usDollars,
+                "$100"
+            ),
+            FormattingCase(
+                56,
+                Currency.Form.usDollars,
+                "$56"
+            ),
+        ).forEach { (amount, form, expected) ->
+            val currency = Currency(amount, form)
+
+            val string = currency.format()
+
+            assertEquals(expected, string)
+        }
+    }
+
+    data class ComparisonCase(
+        val amount1: Long,
+        val form1: Currency.Form,
+        val amount2: Long,
+        val form2: Currency.Form,
+        val expected: Int
+    )
+
+    @Test
+    fun `comparison should `() {
+        listOf(
+            ComparisonCase(
+                1,
+                Currency.Form.usDollars,
+                100,
+                Currency.Form.usDollarCents,
+                0
+            ),
+            ComparisonCase(
+                56,
+                Currency.Form.usDollars,
+                5610,
+                Currency.Form.usDollarCents,
+                -1
+            ),
+            ComparisonCase(
+                56,
+                Currency.Form.usDollarCents,
+                54,
+                Currency.Form.usDollarCents,
+                1
+            ),
+        ).forEach { (amount1, form1, amount2, form2, expected) ->
+
+            val left = Currency(amount1, form1)
+            val right = Currency(amount2, form2)
+            val comparison = left.compareTo(right)
+
+            assertEquals(expected, comparison)
+        }
+    }
+
+    @Test
+    fun `dollars should return a currency with the correct form`() {
+        val amount = 100L
+        val currency = amount.dollars()
+
+        assertEquals(amount, currency.amount)
+        assertEquals(Currency.Form.usDollars, currency.form)
+    }
+
+    @Test
+    fun `cents should return a currency with the correct form`() {
+        val amount = 100L
+        val currency = amount.dollarCents()
+
+        assertEquals(amount, currency.amount)
+        assertEquals(Currency.Form.usDollarCents, currency.form)
+    }
+}