Fix Display-impl of Rollout

3 files changed, 30 insertions, 12 deletions

diff --git a/mullvad-update/mullvad-release/src/main.rs b/mullvad-update/mullvad-release/src/main.rs
index fd0535afe5..cedc426cfa 100644
--- a/mullvad-update/mullvad-release/src/main.rs
+++ b/mullvad-update/mullvad-release/src/main.rs
@@ -129,7 +129,6 @@ pub enum Opt {
         /// By default, any non-zero rollout is accepted.
         /// Setting the value to zero will also show supported versions that have
         /// been released but are currently not being rolled out.
-        // TODO: this prints 0%, but should print 1.1920929e-7
         #[arg(long, default_value_t = mullvad_update::version::SUPPORTED_VERSION)]
         rollout: Rollout,
     },
diff --git a/mullvad-update/src/snapshots/mullvad_update__version__test__rollout_display.snap b/mullvad-update/src/snapshots/mullvad_update__version__test__rollout_display.snap
new file mode 100644
index 0000000000..19319967c9
--- /dev/null
+++ b/mullvad-update/src/snapshots/mullvad_update__version__test__rollout_display.snap
@@ -0,0 +1,10 @@
+---
+source: mullvad-update/src/version.rs
+expression: "&string_reprs"
+---
+-0 => -0
+0 => 0
+0.00000011920929 => 0.00000011920929
+0.33333334 => 0.33333334
+0.9999999 => 0.9999999
+1 => 1
diff --git a/mullvad-update/src/version.rs b/mullvad-update/src/version.rs
index 90e655daf6..9d53406996 100644
--- a/mullvad-update/src/version.rs
+++ b/mullvad-update/src/version.rs
@@ -216,14 +216,12 @@ impl Ord for Rollout {
     }
 }
 
-// TODO: the mullvad-release cli might rely on this being formatted as an f32
 impl Display for Rollout {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "{}%", (self.0 * 100.) as u32)
+        Display::fmt(&self.0, f)
     }
 }
 
-// TODO: the mullvad-release cli might rely on this being formatted as an f32
 impl FromStr for Rollout {
     type Err = anyhow::Error;
 
@@ -267,7 +265,7 @@ pub fn generate_rollout_seed() -> u32 {
 mod test {
     use std::str::FromStr;
 
-    use insta::assert_yaml_snapshot;
+    use insta::{assert_snapshot, assert_yaml_snapshot};
 
     use super::*;
 
@@ -399,13 +397,12 @@ mod test {
     }
 
     const GOOD_ROLLOUT_EXAMPLES: &[f32] = &[
-        -0.0,
-        0.0,
-        -0.0 + f32::EPSILON,
-        1.0,
-        1.0 - 0.0,
-        1.0 - f32::EPSILON,
-        1.0 / 3.0,
+        -0.0,                // 0%
+        0.0,                 // 0%
+        -0.0 + f32::EPSILON, // > 0%
+        1.0 / 3.0,           // 33%
+        1.0 - f32::EPSILON,  // 99%
+        1.0,                 // 100%
     ];
 
     const BAD_ROLLOUT_EXAMPLES: &[f32] = &[
@@ -438,6 +435,18 @@ mod test {
         }
     }
 
+    /// Test that the `Display` impl of [Rollout] makes sense.
+    /// Note clap requires that `Display` must be the inverse of `FromStr`.
+    #[test]
+    fn test_rollout_display() {
+        let string_reprs = GOOD_ROLLOUT_EXAMPLES
+            .iter()
+            .map(|&f| format!("{f} => {}\n", Rollout::try_from(f).unwrap()))
+            .collect::<String>();
+
+        assert_snapshot!(&string_reprs);
+    }
+
     #[test]
     /// Check that the implementation of [rollout_threshold] yields different threshold values as
     /// app version number progresses.