1 files changed, 39 insertions, 1 deletions
diff --git a/macros/src/util/mod.rs b/macros/src/util/mod.rs
index 7ab2185..3557896 100644
--- a/macros/src/util/mod.rs
+++ b/macros/src/util/mod.rs
@@ -26,4 +26,42 @@ macro_rules! or {
     };
 }
 
-pub(crate) use {or, to_option};
+/// Imports the specified item, prepending 'Mock' to the item identifier if the `test`
+/// configuration option is set.
+///
+/// # Examples
+/// ```ignore
+/// use_double!(crate::dependency_history::DependencyHistory);
+/// ```
+/// <br>
+///
+/// Expands to the following when `cfg(not(test))`
+/// ```ignore
+/// use crate::dependency_history::DependencyHistory;
+/// ```
+/// <br>
+///
+/// Expands to the following when `cfg(test)`
+/// ```ignore
+/// use crate::dependency_history::MockDependencyHistory as DependencyHistory;
+/// ```
+macro_rules! use_double {
+    ($([$($part: ident),*])? $item_path_part: ident :: $($next_part: tt)+) => {
+        use_double!(
+            [$($($part,)*)? $item_path_part]
+            $($next_part)+
+        );
+    };
+
+    ([$($part: ident),*] $item_path_part: ident) => {
+        #[cfg(not(test))]
+        use $($part::)* $item_path_part;
+
+        ::paste::paste! {
+            #[cfg(test)]
+            use $($part::)* [<Mock $item_path_part>] as $item_path_part;
+        }
+    };
+}
+
+pub(crate) use {or, to_option, use_double};