add mermaid tests

Author: lmondada

hugr-core/src/hugr/views/render.rs

@@ -417,5 +417,16 @@ mod tests {
         {
             assert!(RenderConfig::try_from(config).is_err());
         }
+
+        #[allow(deprecated)]
+        let config = {
+            let mut config = RenderConfig::default();
+            config.entrypoint = Some(h.entrypoint());
+            config
+        };
+        assert_eq!(
+            MermaidFormatter::from_render_config(config, &h),
+            h.mermaid_format()
+        )
     }
 }

hugr-core/src/hugr/views/rerooted.rs

@@ -233,4 +233,12 @@ mod test {
         );
         assert!(extracted_hugr.get_optype(extracted_bb).is_dataflow_block());
     }
+
+    #[test]
+    fn mermaid_format() {
+        let h = simple_cfg_hugr();
+        let rerooted = h.with_entrypoint(h.entrypoint());
+        let mermaid_str = rerooted.mermaid_format().finish();
+        assert_eq!(mermaid_str, h.mermaid_format().finish());
+    }
 }