add more tests for typical operations (#16)

Author: Byron

src/types.rs

@@ -1,7 +1,7 @@
 use std::collections::HashMap;
 
-use std::fmt;
 use git2::Repository;
+use std::fmt;
 
 /// A wrapper for a repository of the crates.io index.
 pub struct Index {
@@ -23,6 +23,32 @@ pub enum Change {
     Deleted(String),
 }
 
+impl Change {
+    /// Return the added crate, if this is this kind of change.
+    pub fn added(&self) -> Option<&CrateVersion> {
+        match self {
+            Change::Added(v) => Some(v),
+            _ => None,
+        }
+    }
+
+    /// Return the yanked crate, if this is this kind of change.
+    pub fn yanked(&self) -> Option<&CrateVersion> {
+        match self {
+            Change::Yanked(v) => Some(v),
+            _ => None,
+        }
+    }
+
+    /// Return the deleted crate, if this is this kind of change.
+    pub fn deleted(&self) -> Option<&str> {
+        match self {
+            Change::Deleted(v) => Some(v.as_str()),
+            _ => None,
+        }
+    }
+}
+
 impl fmt::Display for Change {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(
@@ -38,7 +64,7 @@ impl fmt::Display for Change {
 }
 
 /// Pack all information we know about a change made to a version of a crate.
-#[derive(Clone, serde::Serialize, serde::Deserialize, Eq, PartialEq, Debug)]
+#[derive(Default, Clone, serde::Serialize, serde::Deserialize, Eq, PartialEq, Debug)]
 pub struct CrateVersion {
     /// The crate name, i.e. `clap`.
     pub name: String,

tests/index/mod.rs

@@ -9,26 +9,57 @@ mod changes_from_objects {
 
     #[test]
     fn addition() -> crate::Result {
-        let _index = index_ro()?;
-        let changes = changes(&_index, "initial commit")?;
+        let changes = changes(&index_ro()?, ":/initial commit")?;
         assert_eq!(changes.len(), 3228);
         assert!(matches!(
-            changes.first().expect("present"),
-            Change::Added(CrateVersion {name, ..}) if name == "gi-get-artifact"
+            changes
+                .first()
+                .and_then(|c| c.added().map(|v| v.name.as_str())),
+            Some("gi-get-artifact")
         ));
         assert!(matches!(
             changes.last().expect("present"),
             Change::Added(CrateVersion {name, ..}) if name == "gizmo"
         ));
         Ok(())
     }
+    #[test]
+    fn deletion() -> crate::Result {
+        let changes = changes(&index_ro()?, "@~326")?;
+        assert_eq!(changes.len(), 1);
+        assert_eq!(changes.first().and_then(|c| c.deleted()), Some("girl"));
+        Ok(())
+    }
+
+    #[test]
+    fn new_version() -> crate::Result {
+        let changes = changes(&index_ro()?, ":/Updating crate `git-repository#0.22.1`")?;
+        assert_eq!(changes.len(), 1);
+        assert_eq!(
+            changes
+                .first()
+                .and_then(|c| c.added().map(|v| v.name.as_str())),
+            Some("git-repository")
+        );
+        Ok(())
+    }
+
+    #[test]
+    fn yanked() -> crate::Result {
+        let changes = changes(&index_ro()?, ":/Yanking crate `github_release_rs#0.1.0`")?;
+        assert_eq!(changes.len(), 1);
+        assert_eq!(
+            changes
+                .first()
+                .and_then(|c| c.yanked().map(|v| v.name.as_str())),
+            Some("github_release_rs")
+        );
+        Ok(())
+    }
 
-    fn changes(index: &Index, commit_message: &str) -> crate::Result<Vec<Change>> {
+    fn changes(index: &Index, revspec: &str) -> crate::Result<Vec<Change>> {
         let repo = git::open(index.repository().path())?;
-        let commit = repo
-            .rev_parse(format!(":/{commit_message}").as_str())?
-            .single()
-            .unwrap();
+        let commit = repo.rev_parse(revspec)?.single().unwrap();
         let ancestor_tree = commit
             .object()?
             .into_commit()