feat: implement test_detached_head_flow

Author: wislertt

tests/integration_tests/flow/scenarios/detached_head.rs

@@ -0,0 +1,40 @@
+// Detached HEAD workflow scenario integration tests
+
+use zerv::cli::flow::test_utils::expect_branch_hash;
+use zerv::test_utils::should_run_docker_tests;
+
+use crate::flow::scenarios::FlowIntegrationTestScenario;
+
+/// Test detached HEAD flow - when there is no branch (detached HEAD state)
+#[test]
+fn test_detached_head_flow() {
+    if !should_run_docker_tests() {
+        return;
+    }
+
+    // Create repo with history
+    let scenario = FlowIntegrationTestScenario::new()
+        .expect("Failed to create test scenario")
+        .create_tag("v1.0.0")
+        .commit()  // Commit after v1.0.0
+        .commit(); // Another commit
+
+    // Get the commit hash for v1.0.0
+    let v1_hash = scenario
+        .get_head_commit()
+        .expect("Failed to get HEAD commit");
+
+    // Checkout to v1.0.0 commit (this creates detached HEAD state)
+    let scenario = scenario.commit().create_tag("v1.1.0");
+
+    let scenario = scenario.checkout(&v1_hash);
+
+    let no_branch_hash = expect_branch_hash("", 5, "34769");
+    // Now we're in detached HEAD state - verify zerv handles it
+    let scenario = scenario.expect_version(
+        &format!("1.0.1-alpha.{}.post.2+2.g{{hex:7}}", no_branch_hash),
+        &format!("1.0.1a{}.post2+2.g{{hex:7}}", no_branch_hash),
+    );
+
+    let _ = scenario;
+}

tests/integration_tests/flow/scenarios/mod.rs

@@ -1,4 +1,5 @@
 pub mod complex_release_branch;
+pub mod detached_head;
 pub mod gitflow;
 pub mod test_utils;
 pub mod trunk_based;

tests/integration_tests/flow/scenarios/test_utils.rs

@@ -106,6 +106,11 @@ impl FlowIntegrationTestScenario {
         self.fixture.path().to_string_lossy().to_string()
     }
 
+    /// Get current HEAD commit hash
+    pub fn get_head_commit(&self) -> Result<String, Box<dyn std::error::Error>> {
+        self.fixture.get_head_commit()
+    }
+
     /// Copy the test repository to a temporary directory for debugging
     /// Creates a copy in .cache/tmp/<tmp_dir_name> that can be inspected manually
     /// If the directory already exists, it will be deleted first