Add test for mapping getter names in Kotlin

testsuite/extra/src/test/java/io/smallrye/config/test/mapping/KotlinMappingGetter.kt

@@ -0,0 +1,34 @@
+package io.smallrye.config.test.mapping
+
+import io.smallrye.config.ConfigMapping
+import io.smallrye.config.SmallRyeConfigBuilder
+import io.smallrye.config.WithDefault
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Test
+
+class KotlinMappingGetter {
+    @Test
+    fun mappingGetterNames() {
+        val config = SmallRyeConfigBuilder()
+            .withMapping(GraphOption::class.java, "graph")
+            .withDefaultValue("graph.get-tenant", "tenant")
+            .withDefaultValue("graph.get-client-id", "id")
+            .withDefaultValue("graph.get-client-secret", "secret")
+            .build()
+
+        val mapping = config.getConfigMapping(GraphOption::class.java)
+        assertEquals("url", mapping.baseUrl)
+        assertEquals("tenant", mapping.tenant)
+        assertEquals("id", mapping.clientId)
+        assertEquals("secret", mapping.clientSecret)
+    }
+
+    @ConfigMapping(prefix = "graph")
+    interface GraphOption {
+        @get:WithDefault("url")
+        val baseUrl: String
+        val tenant: String
+        val clientId: String
+        val clientSecret: String
+    }
+}