semver: add a Version.str() method with unit tests (#12779)

vlib/semver/semver.v

@@ -90,6 +90,16 @@ pub fn (v1 Version) le(v2 Version) bool {
 	return compare_le(v1, v2)
 }
 
+// str returns the `string` representation of the `Version`.
+pub fn (ver Version) str() string {
+	common_string := '${ver.major}.${ver.minor}.$ver.patch'
+
+	prerelease_string := if ver.prerelease.len > 0 { '-$ver.prerelease' } else { '' }
+	metadata_string := if ver.metadata.len > 0 { '+$ver.metadata' } else { '' }
+
+	return '$common_string$prerelease_string$metadata_string'
+}
+
 // * Utilites.
 // coerce converts the `input` version to a `Version` struct.
 // coerce will strip any contents *after* the parsed version string:

vlib/semver/semver_test.v

@@ -86,6 +86,7 @@ fn test_from() {
 		assert ver.patch == item.patch
 		assert ver.metadata == item.metadata
 		assert ver.prerelease == item.prerelease
+		assert ver.str() == item.raw
 	}
 	for ver in invalid_versions_to_test {
 		semver.from(ver) or {