Add IPv4 test case

Cargo.toml

@@ -15,6 +15,9 @@ clippy = {version = "0.0.104", optional = true}
 serde = { version = ">=0.8.0, <2.0", optional = true }
 serde_derive = { version = ">=0.8.0, <2.0", optional = true }
 
+[dev-dependencies]
+serde_json = "*"
+
 [badges]
 travis-ci = { repository = "achanda/ipnetwork" }
 

tests/test_json.rs

@@ -0,0 +1,35 @@
+#[cfg(feature = "with-serde")]
+extern crate serde;
+#[cfg(feature = "with-serde")]
+extern crate serde_json;
+#[cfg(feature = "with-serde")]
+#[macro_use]
+extern crate serde_derive;
+
+extern crate ipnetwork;
+
+
+#[cfg(test)]
+mod tests {
+
+    use ipnetwork::Ipv4Network;
+    use std::net::Ipv4Addr;
+
+    #[cfg(feature = "with-serde")]
+    #[test]
+    fn test_ipv4_json() {
+        let json_string = "{\"ipnetwork\":{\"addr\":\"127.1.0.0\",\"prefix\":24}}";
+
+        #[derive(Serialize, Deserialize)]
+        struct MyStruct {
+            ipnetwork: Ipv4Network,
+        }
+
+        let mystruct: MyStruct = ::serde_json::from_str(json_string).unwrap();
+
+        assert_eq!(mystruct.ipnetwork.ip(), Ipv4Addr::new(127, 1, 0, 0));
+        assert_eq!(mystruct.ipnetwork.prefix(), 24);
+
+        assert_eq!(::serde_json::to_string(&mystruct).unwrap(), json_string);
+    }
+}