1 files changed, 123 insertions, 0 deletions

diff --git a/test_utils/src/git.rs b/test_utils/src/git.rs
new file mode 100644
index 0000000..166693d
--- /dev/null
+++ b/test_utils/src/git.rs
@@ -0,0 +1,123 @@
+//create
+
+// implement drop?
+use std::{env::current_dir, fs, path::PathBuf};
+
+use anyhow::Result;
+use git2::{Oid, RepositoryInitOptions, Signature, Time};
+
+pub struct GitTestRepo {
+    pub dir: PathBuf,
+    pub git_repo: git2::Repository,
+}
+
+impl Default for GitTestRepo {
+    fn default() -> Self {
+        Self::new("main").unwrap()
+    }
+}
+impl GitTestRepo {
+    pub fn new(main_branch_name: &str) -> Result<Self> {
+        let path = current_dir()?.join(format!("tmpgit-{}", rand::random::<u64>()));
+        let git_repo = git2::Repository::init_opts(
+            &path,
+            RepositoryInitOptions::new()
+                .initial_head(main_branch_name)
+                .mkpath(true),
+        )?;
+        Ok(Self {
+            dir: path,
+            git_repo,
+        })
+    }
+
+    pub fn initial_commit(&self) -> Result<Oid> {
+        let oid = self.git_repo.index()?.write_tree()?;
+        let tree = self.git_repo.find_tree(oid)?;
+        let commit_oid = self.git_repo.commit(
+            Some("HEAD"),
+            &joe_signature(),
+            &joe_signature(),
+            "Initial commit",
+            &tree,
+            &[],
+        )?;
+        Ok(commit_oid)
+    }
+
+    pub fn populate(&self) -> Result<Oid> {
+        self.initial_commit()?;
+        fs::write(self.dir.join("t1.md"), "some content")?;
+        self.stage_and_commit("add t1.md")?;
+        fs::write(self.dir.join("t2.md"), "some content1")?;
+        self.stage_and_commit("add t2.md")
+    }
+
+    pub fn stage_and_commit(&self, message: &str) -> Result<Oid> {
+        let prev_oid = self.git_repo.head().unwrap().peel_to_commit()?;
+
+        let mut index = self.git_repo.index()?;
+        index.add_all(["."], git2::IndexAddOption::DEFAULT, None)?;
+        index.write()?;
+
+        let oid = self.git_repo.commit(
+            Some("HEAD"),
+            &joe_signature(),
+            &joe_signature(),
+            message,
+            &self.git_repo.find_tree(index.write_tree()?)?,
+            &[&prev_oid],
+        )?;
+
+        Ok(oid)
+    }
+
+    pub fn create_branch(&self, branch_name: &str) -> Result<()> {
+        self.git_repo
+            .branch(branch_name, &self.git_repo.head()?.peel_to_commit()?, false)?;
+        Ok(())
+    }
+
+    pub fn checkout(&self, ref_name: &str) -> Result<Oid> {
+        let (object, reference) = self.git_repo.revparse_ext(ref_name)?;
+
+        self.git_repo.checkout_tree(&object, None)?;
+
+        match reference {
+            // gref is an actual reference like branches or tags
+            Some(gref) => self.git_repo.set_head(gref.name().unwrap()),
+            // this is a commit, not a reference
+            None => self.git_repo.set_head_detached(object.id()),
+        }?;
+        let oid = self.git_repo.head()?.peel_to_commit()?.id();
+        Ok(oid)
+    }
+}
+
+impl Drop for GitTestRepo {
+    fn drop(&mut self) {
+        let _ = fs::remove_dir_all(&self.dir);
+    }
+}
+pub fn joe_signature() -> Signature<'static> {
+    Signature::new("Joe Bloggs", "joe.bloggs@pm.me", &Time::new(0, 0)).unwrap()
+}
+
+#[cfg(test)]
+mod tests {
+
+    use super::*;
+
+    #[test]
+    fn methods_do_not_throw() -> Result<()> {
+        let repo = GitTestRepo::new("main")?;
+
+        repo.populate()?;
+        repo.create_branch("feature")?;
+        repo.checkout("feature")?;
+        fs::write(repo.dir.join("t3.md"), "some content")?;
+        repo.stage_and_commit("add t3.md")?;
+
+        Ok(())
+    }
+}