add simple test

tests/test_histogramming.py

@@ -0,0 +1,15 @@
+from plothist import make_hist
+import boost_histogram as bh
+
+
+def test_make_hist():
+    """
+    Test make_hist() function.
+    """
+    h = make_hist(data=[0, 1, 2, 3, 4], bins=5, range=(0, 5))
+    assert isinstance(h, bh.Histogram)
+    assert isinstance(h.axes[0], bh.axis.Regular)
+    assert h.sum().value == 5
+    assert h.sum().variance == 5
+    assert h[0].value == 1
+    assert h[-1].value == 1