improve draw tests, revert adding locator argument to draw_mncontour (#…

…681)

.gitignore

@@ -47,3 +47,5 @@ MANIFEST
 htmlcov
 cover
 coverage.xml
+
+tests/fig/*.svg

doc/changelog.rst

@@ -8,11 +8,6 @@ Changelog
 2.8.2 (August 15, 2021)
 -----------------------
 
-Improvements
-~~~~~~~~~~~~
-- ``Minuit.draw_mncontour`` now draws the numerical label on top of the curve by
-  default. The location can be configured with the ``location`` keyword.
-
 Fixes
 ~~~~~
 - ``Minuit.draw_mncontour`` can now be used by passing a single float to keyword ``cl``,

src/iminuit/minuit.py

@@ -1704,7 +1704,7 @@ def draw_contour(
         bound: Union[float, Tuple[Tuple[float, float], Tuple[float, float]]] = 2,
     ) -> Tuple[Collection[float], Collection[float], Collection[Collection[float]]]:
         """
-        Draw 2D contour around minimum (required matplotlib).
+        Draw 2D contour around minimum (requires matplotlib).
 
         See :meth:`contour` for details on parameters and interpretation. Please also read
         the docs of :meth:`mncontour` to understand the difference between the two.
@@ -1806,7 +1806,6 @@ def draw_mncontour(
         *,
         cl: Optional[Iterable[float]] = None,
         size: int = 100,
-        locator="top",
     ) -> Any:
         """
         Draw 2D Minos confidence region (requires matplotlib).
@@ -1827,8 +1826,6 @@ def draw_mncontour(
         size :
             Number of points on each contour(s) (default: 100). Increasing this makes
             the contour smoother, but requires more computation time.
-        locator : str
-            Where to place the numerical label (default: "top").
 
         Examples
         --------
@@ -1845,20 +1842,25 @@ def draw_mncontour(
         mncontour
         """
         from matplotlib import pyplot as plt
+        from matplotlib.path import Path
         from matplotlib.contour import ContourSet
 
         cls = cl if isinstance(cl, Iterable) else [cl]
 
         c_val = []
         c_pts = []
+        codes = []
         for cl in cls:  # type:ignore
             pts = self.mncontour(x, y, cl=cl, size=size)
-            # close curve
-            pts = list(pts)
-            pts.append(pts[0])
+            # add extra point whose coordinates are ignored
+            pts = np.append(pts, pts[:1], axis=0)
             c_val.append(cl if cl is not None else 0.68)
             c_pts.append([pts])  # level can have more than one contour in mpl
-        cs = ContourSet(plt.gca(), c_val, c_pts, locator="top")
+            codes.append(
+                [[Path.MOVETO] + [Path.LINETO] * (size - 2) + [Path.CLOSEPOLY]]
+            )
+        assert len(c_val) == len(codes), f"{len(c_val)} {len(codes)}"
+        cs = ContourSet(plt.gca(), c_val, c_pts, codes)
         plt.clabel(cs)
         plt.xlabel(x)
         plt.ylabel(y)

tests/test_draw.py

@@ -1,57 +1,88 @@
 import pytest
 from iminuit import Minuit
+from pathlib import Path
+import numpy as np
+
 
 mpl = pytest.importorskip("matplotlib")
+plt = pytest.importorskip("matplotlib.pyplot")
 mpl.use("Agg")
 
 
 def f1(x, y):
-    return (1 - x) ** 2 + 100 * (y - 1) ** 2
-
-
-def f2(par):
-    return f1(par[0], par[1])
+    return (1 - x) ** 2 + np.exp((y - 1) ** 2)
 
 
 f1.errordef = 1
-f2.errordef = 1
 
 
-@pytest.fixture(params=("normal", "numpy"))
-def minuit(request):
-    if request.param == "normal":
-        m = Minuit(f1, x=0, y=0)
-    else:
-        m = Minuit(f2, (0, 0), name=("x", "y"))
+@pytest.fixture
+def minuit():
+    m = Minuit(f1, x=0, y=0)
     m.migrad()
     return m
 
 
-def test_profile(minuit):
-    minuit.draw_profile("x")  # plots with hesse errors
+@pytest.fixture
+def fig(request):
+    fig = plt.figure()
+    yield fig
+    p = Path(__file__).parent / "fig"
+    if not p.exists():
+        p.mkdir()
+    fig.savefig(p / (request.node.name + ".svg"))
+    del fig
+
+
+@pytest.mark.parametrize("arg", ("x", "y"))
+def test_profile_1(fig, minuit, arg):
+    # plots with hesse errors
+    minuit.draw_profile(arg)
+    plt.ylim(0, 5)
+
+
+@pytest.mark.parametrize("arg", ("x", "y"))
+def test_profile_2(fig, minuit, arg):
+    # plots with minos errors
     minuit.minos()
-    minuit.draw_profile("x")  # plots with minos errors
+    minuit.draw_profile(arg)
+    plt.ylim(0, 5)
 
 
-def test_mnprofile(minuit):
-    minuit.draw_mnprofile("x")  # plots with hesse errors
+@pytest.mark.parametrize("arg", ("x", "y"))
+def test_mnprofile_1(fig, minuit, arg):
+    # plots with hesse errors
+    minuit.draw_mnprofile(arg)
+    plt.ylim(0, 5)
+
+
+@pytest.mark.parametrize("arg", ("x", "y"))
+def test_mnprofile_2(fig, minuit, arg):
+    # plots with minos errors
     minuit.minos()
-    minuit.draw_mnprofile("x")  # plots with minos errors
+    minuit.draw_mnprofile(arg)
+    plt.ylim(0, 5)
 
 
-def test_mncontour_1(minuit):
+def test_mncontour_1(fig, minuit):
     minuit.draw_mncontour("x", "y")
 
 
-def test_mncontour_2(minuit):
+def test_mncontour_2(fig, minuit):
     minuit.draw_mncontour("x", "y", cl=0.68)
 
 
-def test_mncontour_3(minuit):
+def test_mncontour_3(fig, minuit):
     minuit.draw_mncontour("x", "y", cl=[0.68, 0.9])
 
 
-def test_drawcontour(minuit):
+def test_contour_1(fig, minuit):
     minuit.draw_contour("x", "y")
-    minuit.draw_contour("x", "x", size=20, bound=2)
-    minuit.draw_contour("x", "x", size=20, bound=((-10, 10), (-10, 10)))
+
+
+def test_contour_2(fig, minuit):
+    minuit.draw_contour("x", "y", size=20, bound=2)
+
+
+def test_contour_3(fig, minuit):
+    minuit.draw_contour("x", "y", size=100, bound=((-0.5, 2.5), (-1, 3)))