implement equal

Author: tomoikey

src/rule/length.rs

@@ -1,4 +1,5 @@
 pub use length_definition::*;
 
+mod equal;
 mod length_definition;
 mod less;

src/rule/length/equal.rs

@@ -0,0 +1,66 @@
+#[macro_export]
+macro_rules! length_equal_rule {
+    ($length:literal) => {
+        paste::item! {
+            #[allow(dead_code)]
+            pub type [<LengthEqual $length>]<ITEM> = $crate::Refined<[<LengthEqualRule $length>]<ITEM>>;
+
+            #[allow(dead_code)]
+            pub struct [<LengthEqualRule $length>]<ITEM> {
+                _phantom: ::std::marker::PhantomData<ITEM>,
+            }
+
+            impl<ITEM> $crate::rule::Rule for [<LengthEqualRule $length>]<ITEM> where ITEM: $crate::rule::LengthDefinition {
+                type Item = ITEM;
+                fn validate(target: &Self::Item) -> Result<(), $crate::result::Error> {
+                    if target.length() == $length {
+                        Ok(())
+                    } else {
+                        Err(Error::new(format!("target length is not equal to {}", $length)))
+                    }
+                }
+            }
+        }
+    };
+    ($length:literal, $($lengths:literal),+) => {
+        length_equal_rule!($length);
+        length_equal_rule!($($lengths),+);
+    };
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::result::Error;
+
+    length_equal_rule!(5, 10);
+
+    #[test]
+    fn test_length_equal_5() -> Result<(), Error> {
+        let target = "12345";
+        let refined = LengthEqual5::new(target)?;
+        assert_eq!(refined.into_value(), "12345");
+        Ok(())
+    }
+
+    #[test]
+    fn test_length_equal_5_fail() {
+        let target = "1234";
+        let refined = LengthEqual5::new(target);
+        assert!(refined.is_err());
+    }
+
+    #[test]
+    fn test_length_equal_10() -> Result<(), Error> {
+        let target = "1234567890";
+        let refined = LengthEqual10::new(target)?;
+        assert_eq!(refined.into_value(), "1234567890");
+        Ok(())
+    }
+
+    #[test]
+    fn test_length_equal_10_fail() {
+        let target = "123456789";
+        let refined = LengthEqual10::new(target);
+        assert!(refined.is_err());
+    }
+}