add unit test for KVS

Author: wenxi-zeng

core/src/main/java/com/segment/analytics/kotlin/core/utilities/KVS.kt

@@ -17,6 +17,7 @@ interface KVS {
     fun get(key: String, defaultVal: String?): String?
     fun put(key: String, value: String): Boolean
     fun remove(key: String): Boolean
+    fun contains(key: String): Boolean
 }
 
 class InMemoryPrefs: KVS {
@@ -45,4 +46,6 @@ class InMemoryPrefs: KVS {
         return true
     }
 
+    override fun contains(key: String) = cache.containsKey(key)
+
 }

core/src/main/java/com/segment/analytics/kotlin/core/utilities/PropertiesFile.kt

@@ -72,4 +72,6 @@ class PropertiesFile(val file: File) : KVS {
         save()
         return true
     }
+
+    override fun contains(key: String) = properties.containsKey(key)
 }

core/src/test/kotlin/com/segment/analytics/kotlin/core/utilities/KVSTest.kt

@@ -0,0 +1,48 @@
+package com.segment.analytics.kotlin.core.utilities
+
+import org.junit.jupiter.api.Assertions.*
+import org.junit.jupiter.api.BeforeEach
+import org.junit.jupiter.api.Nested
+import org.junit.jupiter.api.Test
+
+class KVSTest {
+    @Nested
+    inner class InMemoryPrefsTest {
+        private lateinit var prefs: KVS
+
+        @BeforeEach
+        fun setup(){
+            prefs = InMemoryPrefs()
+            prefs.put("int", 1)
+            prefs.put("string", "string")
+        }
+
+        @Test
+        fun getTest() {
+            val keyNotExists = "keyNotExists"
+            val expectedInt = 100
+            val expectedString = "string"
+
+            assertEquals(1, prefs.get("int", 0))
+            assertEquals("string", prefs.get("string", null))
+            assertEquals(0, prefs.get("keyNotExists", 0))
+            assertEquals(null, prefs.get("keyNotExists", null))
+        }
+
+        @Test
+        fun putTest() {
+            prefs.put("int", 2)
+            prefs.put("string", "stringstring")
+
+            assertEquals(2, prefs.get("int", 0))
+            assertEquals("stringstring", prefs.get("string", null))
+        }
+
+        @Test
+        fun containsAndRemoveTest() {
+            assertTrue(prefs.contains("int"))
+            prefs.remove("int")
+            assertFalse(prefs.contains("int"))
+        }
+    }
+}