TST: test_highlight.py convert to functional tests not class

pandas/tests/io/formats/style/test_highlight.py

@@ -5,61 +5,68 @@
 
 pytest.importorskip("jinja2")
 
+from pandas.io.formats.style import Styler
 
-class TestStylerHighlight:
-    def setup_method(self, method):
-        np.random.seed(24)
-        self.s = DataFrame({"A": np.random.permutation(range(6))})
-        self.df = DataFrame({"A": [0, 1], "B": np.random.randn(2)})
 
-    def test_highlight_null(self):
-        df = DataFrame({"A": [0, np.nan]})
-        result = df.style.highlight_null()._compute().ctx
-        expected = {(1, 0): [("background-color", "red")]}
-        assert result == expected
+@pytest.fixture
+def df():
+    return DataFrame({"A": [0, np.nan, 10], "B": [1, None, 2]})
 
-    def test_highlight_null_subset(self):
-        # GH 31345
-        df = DataFrame({"A": [0, np.nan], "B": [0, np.nan]})
-        result = (
-            df.style.highlight_null(null_color="red", subset=["A"])
-            .highlight_null(null_color="green", subset=["B"])
-            ._compute()
-            .ctx
-        )
-        expected = {
-            (1, 0): [("background-color", "red")],
-            (1, 1): [("background-color", "green")],
-        }
-        assert result == expected
 
-    @pytest.mark.parametrize("f", ["highlight_min", "highlight_max"])
-    def test_highlight_minmax_basic(self, f):
-        expected = {
-            (0, 0): [("background-color", "red")],
-            (1, 0): [("background-color", "red")],
-        }
-        if f == "highlight_min":
-            df = -self.df
-        else:
-            df = self.df
-        result = getattr(df.style, f)(axis=1, color="red")._compute().ctx
-        assert result == expected
+@pytest.fixture
+def styler(df):
+    return Styler(df, uuid_len=0)
 
-    @pytest.mark.parametrize("f", ["highlight_min", "highlight_max"])
-    @pytest.mark.parametrize(
-        "kwargs",
-        [
-            {"axis": None, "color": "red"},  # test axis
-            {"axis": 0, "subset": ["A"], "color": "red"},  # test subset
-            {"axis": None, "props": "background-color: red"},  # test props
-        ],
+
+def test_highlight_null(styler):
+    result = styler.highlight_null()._compute().ctx
+    expected = {
+        (1, 0): [("background-color", "red")],
+        (1, 1): [("background-color", "red")],
+    }
+    assert result == expected
+
+
+def test_highlight_null_subset(styler):
+    # GH 31345
+    result = (
+        styler.highlight_null(null_color="red", subset=["A"])
+        .highlight_null(null_color="green", subset=["B"])
+        ._compute()
+        .ctx
     )
-    def test_highlight_minmax_ext(self, f, kwargs):
-        expected = {(1, 0): [("background-color", "red")]}
-        if f == "highlight_min":
-            df = -self.df
-        else:
-            df = self.df
-        result = getattr(df.style, f)(**kwargs)._compute().ctx
-        assert result == expected
+    expected = {
+        (1, 0): [("background-color", "red")],
+        (1, 1): [("background-color", "green")],
+    }
+    assert result == expected
+
+
+@pytest.mark.parametrize("f", ["highlight_min", "highlight_max"])
+def test_highlight_minmax_basic(df, f):
+    expected = {
+        (0, 1): [("background-color", "red")],
+        # ignores NaN row,
+        (2, 0): [("background-color", "red")],
+    }
+    if f == "highlight_min":
+        df = -df
+    result = getattr(df.style, f)(axis=1, color="red")._compute().ctx
+    assert result == expected
+
+
+@pytest.mark.parametrize("f", ["highlight_min", "highlight_max"])
+@pytest.mark.parametrize(
+    "kwargs",
+    [
+        {"axis": None, "color": "red"},  # test axis
+        {"axis": 0, "subset": ["A"], "color": "red"},  # test subset and ignores NaN
+        {"axis": None, "props": "background-color: red"},  # test props
+    ],
+)
+def test_highlight_minmax_ext(df, f, kwargs):
+    expected = {(2, 0): [("background-color", "red")]}
+    if f == "highlight_min":
+        df = -df
+    result = getattr(df.style, f)(**kwargs)._compute().ctx
+    assert result == expected