Add Connection and refactoring EntityCollection

src/test/kotlin/fr/postgresjson/serializer/ConnectionTest.kt

@@ -0,0 +1,30 @@
+package fr.postgresjson.serializer
+
+import fr.postgresjson.connexion.Connection
+import fr.postgresjson.entity.IdEntity
+import org.junit.jupiter.api.Assertions.assertTrue
+import org.junit.jupiter.api.BeforeEach
+import org.junit.jupiter.api.Test
+
+class ConnectionTest() {
+    private lateinit var connection: Connection
+
+    @BeforeEach
+    fun before() {
+        connection = Connection()
+    }
+
+    @Test
+    fun getObject() {
+        val obj: ObjTest? = connection.execute<Int?, ObjTest>("select to_json(a) from test a limit 1")
+        assertTrue(obj is ObjTest)
+    }
+
+//    @Test
+//    fun getExistingObject() {
+//        val obj: ObjTest? = connection.execute<Int?, ObjTest>("select to_json(a) from test a limit 1")
+//        assertTrue(obj is ObjTest)
+//    }
+}
+
+class ObjTest(var name: String): IdEntity()