Add new Kotlin Multiplatform project to gui.

gui/shared/test/PlatformTest.kt

@@ -0,0 +1,17 @@
+package com.hyperling.weather
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertTrue
+
+class PlatformTest {
+    @Test
+    fun `platform name is reported`() {
+        assertTrue(getPlatform().name.isNotBlank())
+    }
+
+    @Test
+    fun `greeting is built from the platform name`() {
+        assertEquals("Hello, ${getPlatform().name}!", Greeting().greet())
+    }
+}