From d5d92d5296634b50eecaf294a9ff2b465da01920 Mon Sep 17 00:00:00 2001
From: Luni-4 <luni-4@hotmail.it>
Date: Mon, 11 Jan 2021 10:38:58 +0100
Subject: [PATCH 1/2] Add a way to compare NAN values in tests

---
 src/macros.rs | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/macros.rs b/src/macros.rs
index a8b1702a8..20c3194fa 100644
--- a/src/macros.rs
+++ b/src/macros.rs
@@ -297,7 +297,12 @@ macro_rules! check_metrics {
 
             $(
                 $(
-                    assert!((func_space.metrics.$metric.$func_float() - $true_float_value).abs() < f64::EPSILON);
+                    let value: f64 = $true_float_value;
+                    if !value.is_nan() {
+                        assert!((func_space.metrics.$metric.$func_float() - value).abs() < f64::EPSILON);
+                    } else {
+                        assert!(func_space.metrics.$metric.$func_float().is_nan());
+                    }
                 )*
             )?
         }

From 946bec0b93291a5a247d9e1c1dd3407720815127 Mon Sep 17 00:00:00 2001
From: Luni-4 <luni-4@hotmail.it>
Date: Mon, 11 Jan 2021 10:41:08 +0100
Subject: [PATCH 2/2] Set cognitive average value to NAN when no functions

---
 src/metrics/cognitive.rs | 50 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)

diff --git a/src/metrics/cognitive.rs b/src/metrics/cognitive.rs
index adee9a135..13ff2f181 100644
--- a/src/metrics/cognitive.rs
+++ b/src/metrics/cognitive.rs
@@ -72,6 +72,8 @@ impl Stats {
     ///
     /// This value is computed dividing the `Cognitive Complexity` value
     /// for the total number of functions/closures in a space.
+    ///
+    /// If there are no functions in a code, its value is `NAN`.
     pub fn cognitive_average(&self) -> f64 {
         self.cognitive() / self.total_space_functions as f64
     }
@@ -411,6 +413,54 @@ mod tests {
 
     use super::*;
 
+    #[test]
+    fn python_no_cognitive() {
+        check_metrics!(
+            "a = 42",
+            "foo.py",
+            PythonParser,
+            cognitive,
+            [(cognitive, 0, usize)],
+            [(cognitive_average, f64::NAN)]
+        );
+    }
+
+    #[test]
+    fn rust_no_cognitive() {
+        check_metrics!(
+            "let a = 42;",
+            "foo.rs",
+            RustParser,
+            cognitive,
+            [(cognitive, 0, usize)],
+            [(cognitive_average, f64::NAN)]
+        );
+    }
+
+    #[test]
+    fn c_no_cognitive() {
+        check_metrics!(
+            "int a = 42;",
+            "foo.c",
+            CppParser,
+            cognitive,
+            [(cognitive, 0, usize)],
+            [(cognitive_average, f64::NAN)]
+        );
+    }
+
+    #[test]
+    fn mozjs_no_cognitive() {
+        check_metrics!(
+            "var a = 42;",
+            "foo.js",
+            MozjsParser,
+            cognitive,
+            [(cognitive, 0, usize)],
+            [(cognitive_average, f64::NAN)]
+        );
+    }
+
     #[test]
     fn python_simple_function() {
         check_metrics!(