Added isError tests

src/main/kotlin/net/thauvin/erik/mobibot/msg/Message.kt

@@ -56,7 +56,7 @@ open class Message @JvmOverloads constructor(
     /** Error flag. */
     var isError = isError
         set(value) {
-            if (value) isNotice = value
+            if (value) isNotice = true
             field = value
         }
 

src/test/kotlin/net/thauvin/erik/mobibot/msg/MessageTest.kt

@@ -39,7 +39,7 @@ import assertk.assertions.isTrue
 import assertk.assertions.prop
 import org.testng.annotations.Test
 
-class TestMessage {
+class MessageTest {
     @Test
     fun testConstructor() {
         var msg = Message("foo")
@@ -61,6 +61,23 @@ class TestMessage {
         }
     }
 
+    @Test
+    fun testIsError() {
+        val msg = Message("foo")
+        msg.isError = true
+        assertThat(msg).all {
+            prop(Message::isError).isTrue()
+            prop(Message::isNotice).isTrue()
+            prop(Message::isPrivate).isFalse()
+        }
+        msg.isError = false
+        assertThat(msg).all {
+            prop(Message::isError).isFalse()
+            prop(Message::isNotice).isTrue()
+            prop(Message::isPrivate).isFalse()
+        }
+    }
+
     @Test
     fun testNoticeMessage() {
         val msg = NoticeMessage("food")