KTLN-836: Introduction to Kluent Assertion Library (#1087)

* KTLN-836: Introduction to Kluent Assertion Library

* Some updates from review feedback

Author: sazzer

kotlin-testing/pom.xml

@@ -105,6 +105,13 @@
             <scope>test</scope>
         </dependency>
 
+        <dependency>
+            <groupId>org.amshove.kluent</groupId>
+            <artifactId>kluent</artifactId>
+            <version>${kluent.version}</version>
+            <scope>test</scope>
+        </dependency>
+
     </dependencies>
 
     <build>
@@ -135,6 +142,7 @@
         <testcontainers.version>1.20.1</testcontainers.version>
         <postgresql.version>42.7.3</postgresql.version>
         <mockk.version>1.12.0</mockk.version>
+        <kluent.version>1.73</kluent.version>
     </properties>
 
 </project>

kotlin-testing/src/test/kotlin/com/baeldung/kluent/EquivalencyUnitTest.kt

@@ -0,0 +1,48 @@
+package com.baeldung.kluent
+
+import org.amshove.kluent.*
+import org.junit.jupiter.api.Disabled
+import org.junit.jupiter.api.Test
+
+class EquivalencyUnitTest {
+    @Test
+    fun `when asserting equality then the equals method should be used`() {
+        val actual = NotAllFieldsChecked("123", "Baeldung", 42)
+
+        actual shouldBeEqualTo NotAllFieldsChecked("123", "Other", 100)
+    }
+
+    @OptIn(ExperimentalStdlibApi::class)
+    @Test
+    @Disabled // We expect this to fail
+    fun `when asserting equivalency then the individual fields should be checked`() {
+        val actual = NotAllFieldsChecked("123", "Baeldung", 42)
+
+        actual.shouldBeEquivalentTo(NotAllFieldsChecked("123", "Other", 100))
+    }
+
+    @OptIn(ExperimentalStdlibApi::class)
+    @Test
+    fun `when asserting equivalency specifying which fields to exclude then only the other fields should be checked`() {
+        val actual = NotAllFieldsChecked("123", "Baeldung", 42)
+
+        actual.shouldBeEquivalentTo(NotAllFieldsChecked("123", "Other", 42)) {
+            it.excluding(NotAllFieldsChecked::name)
+        }
+    }
+
+    class NotAllFieldsChecked(val id: String, val name: String, val age: Int) {
+        override fun equals(other: Any?): Boolean {
+            if (this === other) return true
+            if (javaClass != other?.javaClass) return false
+
+            other as NotAllFieldsChecked
+
+            return id == other.id
+        }
+
+        override fun hashCode(): Int {
+            return id.hashCode()
+        }
+    }
+}

kotlin-testing/src/test/kotlin/com/baeldung/kluent/ExceptionsUnitTest.kt

@@ -0,0 +1,28 @@
+package com.baeldung.kluent
+
+import kotlinx.coroutines.test.runTest
+import org.amshove.kluent.coInvoking
+import org.amshove.kluent.invoking
+import org.amshove.kluent.shouldThrow
+import org.amshove.kluent.withMessage
+import org.junit.jupiter.api.Test
+import java.util.concurrent.TimeoutException
+
+class ExceptionsUnitTest {
+    @Test
+    fun `when a block throws then we should be able to assert the correct exception`() {
+        invoking { 1 / 0 } shouldThrow ArithmeticException::class
+    }
+
+    @Test
+    fun `when a block throws then we should be able to assert the correct exception and message`() {
+        invoking { 1 / 0 } shouldThrow ArithmeticException::class withMessage "/ by zero"
+    }
+
+    @Test
+    fun `when a suspend block throws then we should be able to assert the correct exception`() {
+        runTest {
+            coInvoking { suspend { throw TimeoutException() }() } shouldThrow TimeoutException::class
+        }
+    }
+}

kotlin-testing/src/test/kotlin/com/baeldung/kluent/SimpleAssertionsUnitTest.kt

@@ -0,0 +1,40 @@
+package com.baeldung.kluent
+
+import org.amshove.kluent.*
+import org.junit.jupiter.api.Disabled
+import org.junit.jupiter.api.Test
+
+class SimpleAssertionsUnitTest {
+    @Test
+    @Disabled // We expect this to fail
+    fun `when comparing two strings they they should not be equal`() {
+        val value = "Hello"
+
+        value.shouldBeEqualTo("Expected")
+        value shouldBeEqualTo  "Expected"
+        value `should be equal to` "Expected"
+    }
+
+    @Test
+    fun `when comparing two strings in a case inseneitive manner then they should be equal`() {
+        val value = "Hello"
+
+        value shouldBeEqualToIgnoringCase "Hello"
+        value shouldBeEqualToIgnoringCase "HELLO"
+        value shouldBeEqualToIgnoringCase "hello"
+    }
+
+    @Test
+    @Disabled // We expect this to fail
+    fun `when performing multiple related assertions then they should all run and report together`() {
+        val set = setOf("a", "b", "c")
+
+        assertSoftly {
+            set shouldHaveSize 4
+            set shouldContain "a"
+            set shouldContain "b"
+            set shouldContain "c"
+            set shouldContain "d"
+        }
+    }
+}