Remove function calls inside of 'expect'

src/testing/fixtures.rs

@@ -318,10 +318,12 @@ where
     G::Vertex: Debug,
     G::Edge: Debug,
 {
-    let path = path_option.expect(&format!(
-        "path should exist between source vertex {:?} and connected targets {:?}",
-        source, targets
-    ));
+    let path = path_option.unwrap_or_else(|| {
+        panic!(
+            "path should exist between source vertex {:?} and connected targets {:?}",
+            source, targets
+        )
+    });
 
     if targets.contains(&source) {
         assert!(
@@ -402,9 +404,9 @@ pub fn assert_isomorphic<G: GraphTopology, H: GraphTopology>(
                 .position(|x| {
                     vertex_map(x.vertex) == incidence.vertex && edge_map(x.edge) == incidence.edge
                 })
-                .expect(&format!(
-                    "unexpected incidence {incidence:?} of vertex {v:?} in the other graph"
-                ));
+                .unwrap_or_else(|| {
+                    panic!("unexpected incidence {incidence:?} of vertex {v:?} in the other graph")
+                });
             expected.swap_remove(pos);
         }
         assert!(