diff --git a/tests/test_pr_review_merge_scheduler.py b/tests/test_pr_review_merge_scheduler.py
index 3087b88..f83db9e 100644
--- a/tests/test_pr_review_merge_scheduler.py
+++ b/tests/test_pr_review_merge_scheduler.py
@@ -1,10 +1,16 @@
+import runpy
+from pathlib import Path
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+from scripts.ci import pr_review_merge_scheduler
 from scripts.ci.pr_review_merge_scheduler import opencode_in_progress
 
+
 def test_empty_pr_context():
-    # Empty PR dict
     assert opencode_in_progress({}) is False
 
-    # PR with no context nodes
     pr = {
         "statusCheckRollup": {
             "contexts": {
@@ -14,8 +20,8 @@ def test_empty_pr_context():
     }
     assert opencode_in_progress(pr) is False
 
+
 def test_no_opencode_context():
-    # PR with irrelevant context nodes
     pr = {
         "statusCheckRollup": {
             "contexts": {
@@ -28,6 +34,7 @@ def test_no_opencode_context():
     }
     assert opencode_in_progress(pr) is False
 
+
 def test_opencode_completed_status():
     pr = {
         "statusCheckRollup": {
@@ -43,6 +50,7 @@ def test_opencode_completed_status():
     }
     assert opencode_in_progress(pr) is False
 
+
 def test_opencode_in_progress_status():
     pr1 = {
         "statusCheckRollup": {
@@ -77,6 +85,7 @@ def test_opencode_in_progress_status():
     }
     assert opencode_in_progress(pr3) is False
 
+
 def test_opencode_workflow_name_in_progress():
     pr = {
         "statusCheckRollup": {
@@ -100,6 +109,7 @@ def test_opencode_workflow_name_in_progress():
     }
     assert opencode_in_progress(pr) is True
 
+
 def test_multiple_contexts_one_in_progress():
     pr = {
         "statusCheckRollup": {
@@ -113,3 +123,139 @@ def test_multiple_contexts_one_in_progress():
         }
     }
     assert opencode_in_progress(pr) is True
+
+
+def test_split_repo_success():
+    assert pr_review_merge_scheduler.split_repo("owner/repo") == ("owner", "repo")
+
+
+def test_split_repo_success_multiple_slashes():
+    assert pr_review_merge_scheduler.split_repo("owner/repo/extra") == ("owner", "repo/extra")
+
+
+def test_split_repo_invalid():
+    with pytest.raises(ValueError, match="repo must be owner/name, got 'invalid'"):
+        pr_review_merge_scheduler.split_repo("invalid")
+
+
+def test_split_repo_empty_owner():
+    with pytest.raises(ValueError, match="repo must be owner/name, got '/repo'"):
+        pr_review_merge_scheduler.split_repo("/repo")
+
+
+def test_split_repo_empty_repo():
+    with pytest.raises(ValueError, match="repo must be owner/name, got 'owner/'"):
+        pr_review_merge_scheduler.split_repo("owner/")
+
+
+def test_split_repo_wraps_split_value_error():
+    repo = MagicMock()
+    repo.split.side_effect = ValueError("mocked split error")
+
+    with pytest.raises(ValueError, match=r"repo must be owner/name, got <MagicMock"):
+        pr_review_merge_scheduler.split_repo(repo)
+
+
+def test_error_path(capsys, monkeypatch):
+    monkeypatch.setattr("sys.argv", ["pr_review_merge_scheduler.py", "--repo", "owner/repo"])
+
+    with patch("subprocess.run") as mock_run:
+        mock_process = MagicMock()
+        mock_process.returncode = 1
+        mock_process.stderr = "fake error message"
+        mock_run.return_value = mock_process
+
+        with pytest.raises(SystemExit, match="1") as excinfo:
+            runpy.run_path(
+                str(Path(__file__).parent.parent / "scripts" / "ci" / "pr_review_merge_scheduler.py"),
+                run_name="__main__",
+            )
+
+        assert excinfo.value.code == 1
+
+    captured = capsys.readouterr()
+    assert "Command failed" in captured.err
+    assert "fake error message" in captured.err
+
+
+def test_has_current_head_approval_true_from_review_state():
+    pr = {
+        "headRefOid": "commit123",
+        "reviewDecision": "REVIEW_REQUIRED",
+        "reviews": {
+            "nodes": [
+                {
+                    "state": "APPROVED",
+                    "author": {"login": "opencode-agent"},
+                    "commit": {"oid": "commit123"},
+                }
+            ]
+        }
+    }
+    assert pr_review_merge_scheduler.has_current_head_approval(pr) is True
+
+
+def test_has_current_head_approval_true_from_review_decision():
+    pr = {
+        "headRefOid": "commit123",
+        "reviewDecision": "APPROVED",
+        "reviews": {
+            "nodes": []
+        }
+    }
+    assert pr_review_merge_scheduler.has_current_head_approval(pr) is True
+
+
+def test_has_current_head_approval_false():
+    pr = {
+        "headRefOid": "commit123",
+        "reviewDecision": "REVIEW_REQUIRED",
+        "reviews": {
+            "nodes": [
+                {
+                    "state": "CHANGES_REQUESTED",
+                    "author": {"login": "opencode-agent"},
+                    "commit": {"oid": "commit123"},
+                }
+            ]
+        }
+    }
+    assert pr_review_merge_scheduler.has_current_head_approval(pr) is False
+
+
+def test_has_current_head_approval_wrong_commit():
+    pr = {
+        "headRefOid": "commit123",
+        "reviewDecision": "REVIEW_REQUIRED",
+        "reviews": {
+            "nodes": [
+                {
+                    "state": "APPROVED",
+                    "author": {"login": "opencode-agent"},
+                    "commit": {"oid": "oldcommit456"},
+                }
+            ]
+        }
+    }
+    assert pr_review_merge_scheduler.has_current_head_approval(pr) is False
+
+
+def test_has_current_head_approval_wrong_author():
+    pr = {
+        "headRefOid": "commit123",
+        "reviewDecision": "REVIEW_REQUIRED",
+        "reviews": {
+            "nodes": [
+                {
+                    "state": "APPROVED",
+                    "author": {"login": "some-other-user"},
+                    "commit": {"oid": "commit123"},
+                }
+            ]
+        }
+    }
+    assert pr_review_merge_scheduler.has_current_head_approval(pr) is False
+
+
+def test_has_current_head_approval_missing_keys():
+    assert pr_review_merge_scheduler.has_current_head_approval({}) is False