更新了保存图表模块

tests/test_viz.py

@@ -1,6 +1,7 @@
 """viz 包测试。
 
 绘图测试不比对像素——只验证"能画出来、能存成文件、尺寸符合美赛要求"。
+未实现的函数按决策 26 **逐条** skip，不用模块级 `pytestmark`。
 """
 
 from __future__ import annotations
@@ -11,18 +12,30 @@ matplotlib.use("Agg")
 
 import pytest
 
-pytestmark = pytest.mark.skip(reason="未实现：见 docs/03-roadmap.md L0/L1")
+_NOT_IMPLEMENTED = "未实现：见 docs/03-roadmap.md L0/L1"
 
 
+@pytest.fixture
+def fig():
+    """最小 Figure；测试结束统一关闭，避免 matplotlib 的"图开太多"告警。"""
+    import matplotlib.pyplot as plt
+
+    figure, _ = plt.subplots(figsize=(2, 2))
+    yield figure
+    plt.close(figure)
+
+
+@pytest.mark.skip(reason=_NOT_IMPLEMENTED)
 @pytest.mark.parametrize("kind", ["line", "scatter", "hist", "box", "bar"])
 def test_plot_kinds_produce_figure(kind, rng):
     from mcm_toolkit.viz import plot
 
     x = rng.normal(size=100)
-    fig, ax = plot(x, x, kind=kind)
-    assert fig is not None and ax is not None
+    figure, ax = plot(x, x, kind=kind)
+    assert figure is not None and ax is not None
 
 
+@pytest.mark.skip(reason=_NOT_IMPLEMENTED)
 def test_mcm_style_sets_300dpi():
     from mcm_toolkit.viz import mcm_style
 
@@ -31,15 +44,93 @@ def test_mcm_style_sets_300dpi():
     assert matplotlib.rcParams["font.size"] >= 8.0
 
 
-def test_save_figure_writes_png_and_pdf(tmp_path, rng):
-    from mcm_toolkit.viz import plot, save_figure
+def test_save_figure_writes_png_and_pdf(fig, tmp_path):
+    from mcm_toolkit.viz import save_figure
 
-    fig, _ = plot(rng.normal(size=50), rng.normal(size=50), kind="scatter")
     paths = save_figure(fig, tmp_path / "fig1", formats=("png", "pdf"))
-    assert {p.suffix for p in paths} == {".png", ".pdf"}
+    assert [p.suffix for p in paths] == [".png", ".pdf"]
     assert all(p.exists() and p.stat().st_size > 0 for p in paths)
 
 
+def test_save_figure_strips_an_image_suffix_from_path(fig, tmp_path):
+    """`fig1.png` 当主干用：不能写出 `fig1.png.png`。"""
+    from mcm_toolkit.viz import save_figure
+
+    paths = save_figure(fig, tmp_path / "fig1.png", formats=("pdf",))
+    assert paths == [tmp_path / "fig1.pdf"]
+    assert paths[0].exists()
+
+
+def test_save_figure_creates_parent_directories(fig, tmp_path):
+    from mcm_toolkit.viz import save_figure
+
+    target = tmp_path / "nested" / "deeper" / "fig1"
+    paths = save_figure(fig, target, formats=("png",))
+    assert paths[0] == tmp_path / "nested" / "deeper" / "fig1.png"
+    assert paths[0].exists()
+
+
+def test_save_figure_normalizes_format_case_and_keeps_order(fig, tmp_path):
+    from mcm_toolkit.viz import save_figure
+
+    paths = save_figure(fig, tmp_path / "fig1", formats=("PDF", "png"))
+    assert [p.suffix for p in paths] == [".pdf", ".png"]
+    assert all(p.exists() for p in paths)
+
+
+def test_save_figure_rejects_a_single_string_as_formats(fig, tmp_path):
+    from mcm_toolkit.viz import save_figure
+
+    with pytest.raises(TypeError, match="不要传单个字符串"):
+        save_figure(fig, tmp_path / "fig1", formats="png")  # type: ignore[arg-type]
+
+
+def test_save_figure_rejects_bad_formats(fig, tmp_path):
+    from mcm_toolkit.viz import save_figure
+
+    with pytest.raises(ValueError, match="不能为空"):
+        save_figure(fig, tmp_path / "fig1", formats=())
+    with pytest.raises(ValueError, match="不支持"):
+        save_figure(fig, tmp_path / "fig1", formats=("gif",))
+    with pytest.raises(ValueError, match="重复"):
+        save_figure(fig, tmp_path / "fig1", formats=("png", "PNG"))
+
+
+def test_save_figure_validates_before_creating_directories(fig, tmp_path):
+    """格式错时不能先建目录留下副作用。"""
+    from mcm_toolkit.viz import save_figure
+
+    nested = tmp_path / "should_not_exist" / "fig1"
+    with pytest.raises(ValueError, match="不支持"):
+        save_figure(fig, nested, formats=("gif",))
+    assert not nested.parent.exists()
+
+
+def test_save_figure_rejects_bad_render_options(fig, tmp_path):
+    from mcm_toolkit.viz import save_figure
+
+    with pytest.raises(TypeError, match="dpi"):
+        save_figure(fig, tmp_path / "fig1", dpi=300.0)  # type: ignore[arg-type]
+    with pytest.raises(TypeError, match="dpi"):
+        save_figure(fig, tmp_path / "fig1", dpi=True)
+    with pytest.raises(ValueError, match="dpi"):
+        save_figure(fig, tmp_path / "fig1", dpi=0)
+    with pytest.raises(TypeError, match="bbox_inches"):
+        save_figure(fig, tmp_path / "fig1", bbox_inches=3)  # type: ignore[arg-type]
+    with pytest.raises(ValueError, match="bbox_inches"):
+        save_figure(fig, tmp_path / "fig1", bbox_inches="")
+    with pytest.raises(TypeError, match="transparent"):
+        save_figure(fig, tmp_path / "fig1", transparent="yes")  # type: ignore[arg-type]
+
+
+def test_save_figure_rejects_non_figure(tmp_path):
+    from mcm_toolkit.viz import save_figure
+
+    with pytest.raises(TypeError, match="Figure"):
+        save_figure(object(), tmp_path / "fig1")  # type: ignore[arg-type]
+
+
+@pytest.mark.skip(reason=_NOT_IMPLEMENTED)
 def test_save_table_writes_latex_with_caption(tmp_path):
     import pandas as pd