implement not_equal

Author: intarga

src/checks/consistency.rs

@@ -13,5 +13,8 @@ pub use min_less_than_single::min_less_than_single;
 mod max_less_than_single;
 pub use max_less_than_single::max_less_than_single;
 
+mod not_equal;
+pub use not_equal::not_equal;
+
 // TODO: Figure out the ideal container type (Analogous to [`crate::DataCache`]) to pass large
 // amounts of data into consistency checks

src/checks/consistency/not_equal.rs

@@ -0,0 +1,34 @@
+use crate::Flag;
+
+/// Consistency check between 2 climate parameters, where both should be within a threshold of
+/// each other.
+///
+/// Useful for comparing observations against model data, or comparing two instruments measuring
+/// the same climate parameter at the same site.
+///
+/// Returns [`Flag::DataMissing`] if either datum is missing,
+/// [`Flag::Fail`] if the difference between datum1 and datum2 is greater than threshold,
+/// [`Flag::Pass`] otherwise.
+pub fn not_equal(datum1: Option<f32>, datum2: Option<f32>, threshold: f32) -> Flag {
+    if datum1.is_none() || datum2.is_none() {
+        return Flag::DataMissing;
+    }
+
+    if (datum1.unwrap() - datum2.unwrap()).abs() > threshold {
+        Flag::Fail
+    } else {
+        Flag::Pass
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_not_equal() {
+        assert_eq!(not_equal(Some(1.), Some(1.1), 0.2), Flag::Pass);
+        assert_eq!(not_equal(Some(1.), Some(1.2), 0.1), Flag::Fail);
+        assert_eq!(not_equal(Some(1.), None, 0.1), Flag::DataMissing);
+    }
+}