diff --git a/src/bin/evalexpr.rs b/src/bin/evalexpr.rs
index ac1ee3f3..f1668d70 100644
--- a/src/bin/evalexpr.rs
+++ b/src/bin/evalexpr.rs
@@ -1,3 +1,4 @@
+#![cfg(not(tarpaulin_include))]
 pub fn main() -> Result<(), Box<dyn std::error::Error>> {
     let args = std::env::args().skip(1).collect::<Vec<String>>().join(" ");
 
diff --git a/src/feature_serde/mod.rs b/src/feature_serde/mod.rs
index 88a5a7c2..112cbf08 100644
--- a/src/feature_serde/mod.rs
+++ b/src/feature_serde/mod.rs
@@ -33,3 +33,32 @@ impl<NumericTypes: EvalexprNumericTypes> de::Visitor<'_> for NodeVisitor<Numeric
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use std::{
+        fmt::{Debug, Formatter, Write},
+        marker::PhantomData,
+    };
+
+    use serde::de::Visitor;
+
+    use crate::DefaultNumericTypes;
+
+    use super::NodeVisitor;
+
+    #[test]
+    fn node_visitor() {
+        struct Debugger;
+
+        impl Debug for Debugger {
+            fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+                NodeVisitor::<DefaultNumericTypes>(PhantomData).expecting(f)
+            }
+        }
+
+        let mut output = String::new();
+        write!(output, "{:?}", Debugger).unwrap();
+        assert!(!output.is_empty());
+    }
+}
diff --git a/tests/integration.rs b/tests/integration.rs
index 977f293b..9cea35cb 100644
--- a/tests/integration.rs
+++ b/tests/integration.rs
@@ -2500,3 +2500,47 @@ fn test_clear() {
     assert!(context.get_value("five").is_none());
     assert!(eval_with_context("abc(5)", &context).is_err());
 }
+
+#[test]
+fn test_iter_empty_contexts() {
+    assert_eq!(
+        EmptyContext::<DefaultNumericTypes>::default()
+            .iter_variables()
+            .next(),
+        None
+    );
+    assert_eq!(
+        EmptyContext::<DefaultNumericTypes>::default()
+            .iter_variable_names()
+            .next(),
+        None
+    );
+    assert_eq!(
+        EmptyContextWithBuiltinFunctions::<DefaultNumericTypes>::default()
+            .iter_variables()
+            .next(),
+        None
+    );
+    assert_eq!(
+        EmptyContextWithBuiltinFunctions::<DefaultNumericTypes>::default()
+            .iter_variable_names()
+            .next(),
+        None
+    );
+}
+
+#[test]
+fn test_empty_context_builtin_functions() {
+    assert!(EmptyContext::<DefaultNumericTypes>::default().are_builtin_functions_disabled());
+    assert!(
+        !EmptyContextWithBuiltinFunctions::<DefaultNumericTypes>::default()
+            .are_builtin_functions_disabled()
+    );
+}
+
+#[test]
+fn test_compare_different_numeric_types() {
+    assert_eq!(eval("1 < 2.0"), Ok(true.into()));
+    assert_eq!(eval("1 >= 2"), Ok(false.into()));
+    assert_eq!(eval("1 >= 2.0"), Ok(false.into()));
+}