feat: impl Add for Price

src/types/currency.rs

@@ -2,7 +2,7 @@
 //
 // SPDX-License-Identifier: AGPL-3.0-or-later
 
-use std::str::FromStr;
+use std::{ops::Add, str::FromStr};
 
 use async_trait::async_trait;
 use cqrs_es::Aggregate;
@@ -62,6 +62,16 @@ impl Price {
     }
 }
 
+impl Add for Price {
+    type Output = Self;
+    fn add(self, rhs: Self) -> Self::Output {
+        let self_minor = self.major_as_minor() + self.minor;
+        let rhs_minor = rhs.major_as_minor() + rhs.minor;
+
+        Self::from_minor(self_minor + rhs_minor, self.currency)
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -110,4 +120,70 @@ mod tests {
             }
         );
     }
+
+    #[test]
+    fn test_price_add() {
+        let a = Price {
+            minor: 10,
+            major: 100,
+            currency: Currency::INR,
+        };
+
+        let b = Price {
+            minor: 1,
+            major: 200,
+            currency: Currency::INR,
+        };
+
+        assert_eq!(
+            a + b,
+            Price {
+                minor: 11,
+                major: 300,
+                currency: Currency::INR
+            }
+        );
+    }
+
+    #[test]
+    fn test_price_add_zero() {
+        let a = Price {
+            minor: 0,
+            major: 0,
+            currency: Currency::INR,
+        };
+
+        assert_eq!(
+            a.clone() + a,
+            Price {
+                minor: 0,
+                major: 0,
+                currency: Currency::INR
+            }
+        );
+    }
+
+    #[test]
+    fn test_price_add_overflow() {
+        let a = Price {
+            minor: 80,
+            major: 100,
+            currency: Currency::INR,
+        };
+
+        let b = Price {
+            minor: 80,
+            major: 200,
+            currency: Currency::INR,
+        };
+
+        assert_eq!(
+            a + b,
+            Price {
+                minor: 60,
+                major: 301,
+                currency: Currency::INR
+            }
+        );
+    }
 }