SCALA-620: Companion code for the Scala Test Assertions Article

scala-test/src/main/scala-2/com/baeldung/scala/assertions/CurrencyDSL.scala

@@ -0,0 +1,17 @@
+package com.baeldung.scala.assertions
+
+sealed trait Currency
+case object USD extends Currency
+case object EUR extends Currency
+
+case class CurrencyAmount[C <: Currency](amount: Double, cur: C) {
+  def +(other: CurrencyAmount[C]): CurrencyAmount[C] =
+    CurrencyAmount(this.amount + other.amount, this.cur)
+}
+
+object Currency {
+  implicit class RichDouble(value: Double) {
+    def usd: CurrencyAmount[USD.type] = CurrencyAmount(value, USD)
+    def eur: CurrencyAmount[EUR.type] = CurrencyAmount(value, EUR)
+  }
+}

scala-test/src/test/scala-2/com/baeldung/scala/assertions/AssertionsTests.scala

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+package com.baeldung.scala.assertions
+
+import org.scalatest.flatspec.AnyFlatSpec
+import org.scalatest.matchers.should.Matchers
+import org.scalatest.exceptions.TestFailedException
+
+class AssertionsTests extends AnyFlatSpec with Matchers {
+
+  def parseAge(ageString: String): Int = {
+    if (ageString.isEmpty)
+      throw new IllegalArgumentException(
+        "Cannot convert and empty String to an age"
+      )
+    val age = ageString.toInt
+    if (age < 0) throw new IllegalArgumentException("Age cannot be negative")
+    age
+  }
+
+  "An assert" should "pass when the condition is true" in {
+    val sum = 1 + 1
+    assert(sum == 2)
+  }
+
+  "assertResult" should "pass when the code block produces the expected value" in {
+    assertResult(7) {
+      val sum = 3 + 4
+      sum
+    }
+  }
+
+  "assertThrows" should "pass when the correct exception type is thrown" in {
+    assertThrows[IllegalArgumentException] {
+      parseAge("-5")
+    }
+  }
+
+  "withClue" should "provide additional information in case of test failure" in {
+    withClue(
+      "Parsing an empty input should throw an IllegalArgumentException: "
+    ) {
+      try {
+        parseAge("")
+      } catch {
+        case e: IllegalArgumentException =>
+          assert(
+            e.getMessage().equals("Cannot convert and empty String to an age")
+          )
+      }
+    }
+  }
+}

scala-test/src/test/scala-2/com/baeldung/scala/assertions/CurrencyTests.scala

@@ -0,0 +1,22 @@
+package com.baeldung.scala.assertions
+
+import org.scalatest.flatspec.AnyFlatSpec
+import org.scalatest.matchers.should.Matchers
+
+class CurrencyTests extends AnyFlatSpec with Matchers {
+  import Currency.RichDouble
+
+  "Currency DSL" should "allow adding amounts of the same currency" in {
+    val a = 80.0.usd
+    val b = 70.0.usd
+    (a + b) should be(150.0.usd)
+  }
+
+  it should "not compile when trying to add different currencies" in {
+    assertDoesNotCompile("50.0.usd + 100.0.eur")
+  }
+
+  it should "not compile due to a type error when adding different currencies" in {
+    assertTypeError("50.usd + 100.eur")
+  }
+}