Add tests for help (#387)

* Add tests for `levenshtein_distance`-function.

* Add tests for `Matrix`-struct.

1 files changed, 81 insertions, 0 deletions

diff --git a/src/framework/standard/help_commands.rs b/src/framework/standard/help_commands.rs
index 7104525..ccd1e51 100644
--- a/src/framework/standard/help_commands.rs
+++ b/src/framework/standard/help_commands.rs
@@ -844,3 +844,84 @@ pub fn plain<H: BuildHasher>(
 
     Ok(())
 }
+
+
+#[cfg(test)]
+mod levenshtein_tests {
+    use super::levenshtein_distance;
+
+    #[test]
+    fn reflexive() {
+        let word_a = "rusty ferris";
+        let word_b = "rusty ferris";
+        assert_eq!(0, levenshtein_distance(&word_a, &word_b));
+
+        let word_a = "";
+        let word_b = "";
+        assert_eq!(0, levenshtein_distance(&word_a, &word_b));
+
+        let word_a = "rusty ferris";
+        let word_b = "RuSty FerriS";
+        assert_eq!(4, levenshtein_distance(&word_a, &word_b));
+    }
+
+    #[test]
+    fn symmetric() {
+        let word_a = "ferris";
+        let word_b = "rusty ferris";
+        assert_eq!(6, levenshtein_distance(&word_a, &word_b));
+
+        let word_a = "rusty ferris";
+        let word_b = "ferris";
+        assert_eq!(6, levenshtein_distance(&word_a, &word_b));
+
+        let word_a = "";
+        let word_b = "ferris";
+        assert_eq!(6, levenshtein_distance(&word_a, &word_b));
+
+        let word_a = "ferris";
+        let word_b = "";
+        assert_eq!(6, levenshtein_distance(&word_a, &word_b));
+    }
+
+    #[test]
+    fn transitive() {
+        let word_a = "ferris";
+        let word_b = "turbo fish";
+        let word_c = "unsafe";
+
+        let distance_of_a_c = levenshtein_distance(&word_a, &word_c);
+        let distance_of_a_b = levenshtein_distance(&word_a, &word_b);
+        let distance_of_b_c = levenshtein_distance(&word_b, &word_c);
+
+        assert!(distance_of_a_c <= (distance_of_a_b + distance_of_b_c));
+    }
+}
+
+#[cfg(test)]
+mod matrix_tests {
+    use super::Matrix;
+
+    #[test]
+    fn index_mut() {
+        let mut matrix = Matrix::new(5, 5);
+        assert_eq!(matrix[(1, 1)], 0);
+
+        matrix[(1, 1)] = 10;
+        assert_eq!(matrix[(1, 1)], 10);
+    }
+
+    #[test]
+    #[should_panic(expected = "the len is 4 but the index is 9")]
+    fn panic_index_too_high() {
+        let matrix = Matrix::new(2, 2);
+        matrix[(3, 3)];
+    }
+
+    #[test]
+    #[should_panic(expected = "the len is 0 but the index is 0")]
+    fn panic_indexing_when_empty() {
+        let matrix = Matrix::new(0, 0);
+        matrix[(0, 0)];
+    }
+}