fix: add missing tests

src/lib.rs

@@ -0,0 +1,2 @@
+pub mod slugify;
+pub use crate::slugify::slugify;

src/main.rs

@@ -1,29 +1,11 @@
 use clap::Parser;
+use slugify::slugify;
 
 #[derive(Parser)]
 struct Cli {
     strings: Vec<String>,
 }
 
-fn slugify(input: String) -> String {
-    let mut result = input.to_lowercase();
-
-    result = result.replace(' ', "-");
-    result = result
-        .chars()
-        .filter(|&c| c.is_alphanumeric() || c == '_' || c == '-')
-        .collect();
-
-    while result.contains("--") {
-        result = result.replace("--", "-");
-    }
-
-    result = result
-        .trim_matches(|c| c == ' ' || c == '-' || c == '_')
-        .to_string();
-    result
-}
-
 fn main() {
     let args = Cli::parse();
     let combined = args.strings.join(" ");

src/slugify.rs

@@ -0,0 +1,91 @@
+pub fn slugify(input: String) -> String {
+    let mut result = input.to_lowercase();
+
+    result = result.replace(' ', "-");
+    result = result
+        .chars()
+        .filter(|&c| c.is_alphanumeric() || c == '_' || c == '-')
+        .collect();
+
+    while result.contains("--") {
+        result = result.replace("--", "-");
+    }
+
+    result = result
+        .trim_matches(|c| c == ' ' || c == '-' || c == '_')
+        .to_string();
+    result
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_lowercase_conversion() {
+        assert_eq!(slugify("Hello".to_string()), "hello");
+        assert_eq!(slugify("WORLD".to_string()), "world");
+        assert_eq!(slugify("MiXeD".to_string()), "mixed");
+    }
+
+    #[test]
+    fn test_space_to_hyphen() {
+        assert_eq!(slugify("hello world".to_string()), "hello-world");
+        assert_eq!(slugify("multiple   spaces".to_string()), "multiple-spaces");
+    }
+
+    #[test]
+    fn test_trim_trailing_spaces() {
+        assert_eq!(
+            slugify("  trailing     spaces    ".to_string()),
+            "trailing-spaces"
+        );
+    }
+
+    #[test]
+    fn test_special_character_removal() {
+        assert_eq!(slugify("hello!@#$%^&*()world".to_string()), "helloworld");
+        assert_eq!(
+            slugify("keep_underscore-hyphen".to_string()),
+            "keep_underscore-hyphen"
+        );
+        assert_eq!(
+            slugify("remove.comma,semicolon;".to_string()),
+            "removecommasemicolon"
+        );
+    }
+
+    #[test]
+    fn test_consecutive_hyphen_replacement() {
+        assert_eq!(slugify("hello--world".to_string()), "hello-world");
+        assert_eq!(
+            slugify("multiple---hyphens".to_string()),
+            "multiple-hyphens"
+        );
+    }
+
+    #[test]
+    fn test_trim_special_characters() {
+        assert_eq!(slugify("-hello-".to_string()), "hello");
+        assert_eq!(slugify("_world_".to_string()), "world");
+        assert_eq!(slugify(" spaces ".to_string()), "spaces");
+        assert_eq!(slugify("-_-mixed_-_".to_string()), "mixed");
+    }
+
+    #[test]
+    fn test_complex_cases() {
+        assert_eq!(
+            slugify("  Hello, World! This is a Test  ".to_string()),
+            "hello-world-this-is-a-test"
+        );
+        assert_eq!(
+            slugify("__Special-CHARS-123!@#".to_string()),
+            "special-chars-123"
+        );
+        assert_eq!(
+            slugify("Multiple   spaces and---hyphens".to_string()),
+            "multiple-spaces-and-hyphens"
+        );
+        assert_eq!(slugify("".to_string()), "");
+    }
+}