tests: test names of loaded layers in signal integrity test test

tests/multilayer.rs

@@ -1,3 +1,5 @@
+use topola::board::mesadata::MesadataTrait;
+
 mod common;
 
 #[test]
@@ -12,4 +14,38 @@ fn test_signal_integrity_test() {
     let mut invoker = common::load_design_and_assert(
         "tests/multilayer/data/signal_integrity_test/signal_integrity_test.dsn",
     );
+
+    assert_eq!(
+        invoker
+            .autorouter()
+            .board()
+            .layout()
+            .drawing()
+            .layer_count(),
+        4
+    );
+
+    for layer in 0..invoker
+        .autorouter()
+        .board()
+        .layout()
+        .drawing()
+        .layer_count()
+    {
+        let layername = invoker
+            .autorouter()
+            .board()
+            .mesadata()
+            .layer_layername(layer);
+
+        if layer == 0 {
+            assert_eq(layername, "F.Cu");
+        } else if layer == 1 {
+            assert_eq(layername, "In1.Cu");
+        } else if layer == 2 {
+            assert_eq(layername, "In2.Cu");
+        } else if layer == 3 {
+            assert_eq(layername, "B.Cu");
+        }
+    }
 }