ai-agent-book 精选快照（<2MB 代码与文档，来自 github.com/bojieli/ai-agent-book）

chapter5/coding-agent/tests/test_grep_head_limit_zero.py

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+"""head_limit=0 must return zero results (like `head -0`), not unlimited."""
+
+
+def test_head_limit_zero_files_with_matches(system_state, sample_files):
+    from tools.grep_tool import GrepTool
+
+    result = GrepTool(system_state).execute(
+        {
+            "pattern": "ERROR",
+            "path": str(sample_files["text_file1"].parent),
+            "head_limit": 0,
+            "output_mode": "files_with_matches",
+        }
+    )
+    assert result.data["matches"] == 0
+    assert result.data["output"] == "No matches found."
+
+
+def test_head_limit_one_still_caps(system_state, sample_files):
+    from tools.grep_tool import GrepTool
+
+    result = GrepTool(system_state).execute(
+        {
+            "pattern": "ERROR",
+            "path": str(sample_files["text_file1"].parent),
+            "head_limit": 1,
+            "output_mode": "files_with_matches",
+        }
+    )
+    assert result.data["matches"] == 1
+
+
+def test_omitted_head_limit_still_unlimited(system_state, sample_files):
+    from tools.grep_tool import GrepTool
+
+    result = GrepTool(system_state).execute(
+        {
+            "pattern": "test",
+            "path": str(sample_files["text_file1"].parent),
+            "output_mode": "files_with_matches",
+        }
+    )
+    assert result.data["matches"] >= 1