Merge pull request #1 from sushant57/kotlin_string_comparison

Kotlin string comparison

core-kotlin/src/test/kotlin/com/baeldung/stringcomparison/StringComparisonTest.kt

@@ -0,0 +1,47 @@
+package com.baeldung.stringcomparison
+
+import org.junit.Test
+import kotlin.test.assertFalse
+import kotlin.test.assertTrue
+
+class StringComparisonUnitTest {
+
+    @Test
+    fun `compare using equals operator`() {
+        val first = "kotlin"
+        val second = "kotlin"
+        val firstCapitalized = "KOTLIN"
+        assertTrue { first == second }
+        assertFalse { first == firstCapitalized }
+    }
+
+    @Test
+    fun `compare using referential equals operator`() {
+        val first = "kotlin"
+        val second = "kotlin"
+        val copyOfFirst = buildString { "kotlin" }
+        assertTrue { first === second }
+        assertFalse { first === copyOfFirst }
+    }
+
+    @Test
+    fun `compare using equals method`() {
+        val first = "kotlin"
+        val second = "kotlin"
+        val firstCapitalized = "KOTLIN"
+        assertTrue { first.equals(second) }
+        assertFalse { first.equals(firstCapitalized) }
+        assertTrue { first.equals(firstCapitalized, true) }
+    }
+
+    @Test
+    fun `compare using compare method`() {
+        val first = "kotlin"
+        val second = "kotlin"
+        val firstCapitalized = "KOTLIN"
+        assertTrue { first.compareTo(second) == 0 }
+        assertTrue { first.compareTo(firstCapitalized) == 32 }
+        assertTrue { firstCapitalized.compareTo(first) == -32 }
+        assertTrue { first.compareTo(firstCapitalized, true) == 0 }
+    }
+}