diff --git a/skimage/exposure/_adapthist.py b/skimage/exposure/_adapthist.py
index 88729ce2..346d8424 100644
--- a/skimage/exposure/_adapthist.py
+++ b/skimage/exposure/_adapthist.py
@@ -158,11 +158,11 @@ def _clahe(image, ntiles_x, ntiles_y, clip_limit, nbins=128):
     for y in range(ntiles_y + 1):
         xstart = 0
         if y == 0:  # special case: top row
-            ystep = y_size / 2
+            ystep = y_size / 2.0
             yU = 0
             yB = 0
         elif y == ntiles_y:  # special case: bottom row
-            ystep = y_size / 2
+            ystep = y_size / 2.0
             yU = ntiles_y - 1
             yB = yU
         else:  # default values
@@ -172,11 +172,11 @@ def _clahe(image, ntiles_x, ntiles_y, clip_limit, nbins=128):
 
         for x in range(ntiles_x + 1):
             if x == 0:  # special case: left column
-                xstep = x_size / 2
+                xstep = x_size / 2.0
                 xL = 0
                 xR = 0
             elif x == ntiles_x:  # special case: right column
-                xstep = x_size / 2
+                xstep = x_size / 2.0
                 xL = ntiles_x - 1
                 xR = xL
             else:  # default values
@@ -226,7 +226,7 @@ def clip_histogram(hist, clip_limit):
     n_excess = excess.sum() - excess.size * clip_limit
 
     # Second part: clip histogram and redistribute excess pixels in each bin
-    bin_incr = n_excess / hist.size  # average binincrement
+    bin_incr = int(n_excess / hist.size)  # average binincrement
     upper = clip_limit - bin_incr  # Bins larger than upper set to cliplimit
 
     hist[excess_mask] = clip_limit
diff --git a/skimage/exposure/tests/test_exposure.py b/skimage/exposure/tests/test_exposure.py
index a5d72cbb..086739de 100644
--- a/skimage/exposure/tests/test_exposure.py
+++ b/skimage/exposure/tests/test_exposure.py
@@ -87,8 +87,9 @@ def test_adapthist_scalar():
     full_scale = skimage.exposure.rescale_intensity(skimage.img_as_uint(img))
 
     assert_almost_equal = np.testing.assert_almost_equal
-    assert peak_snr(full_scale, adapted) > 95.0
-    assert norm_brightness_err(full_scale, adapted) < 0.05
+    assert_almost_equal(peak_snr(full_scale, adapted), 101.231, 3)
+    assert_almost_equal(norm_brightness_err(full_scale, adapted),
+                        0.041, 3)
     return img, adapted
 
 
@@ -102,8 +103,8 @@ def test_adapthist_grayscale():
                         nbins=128)
     assert_almost_equal = np.testing.assert_almost_equal
     assert img.shape == adapted.shape
-    assert peak_snr(img, adapted) > 95.0
-    assert norm_brightness_err(img, adapted) < 0.05
+    assert_almost_equal(peak_snr(img, adapted), 97.531, 3)
+    assert_almost_equal(norm_brightness_err(img, adapted), 0.0313, 3)
     return data, adapted
 
 
@@ -117,8 +118,9 @@ def test_adapthist_color():
     assert adapted.max() == 1.0
     assert img.shape == adapted.shape
     full_scale = skimage.exposure.rescale_intensity(img)
-    assert peak_snr(img, adapted) > 95.0
-    assert norm_brightness_err(img, adapted) < 0.05
+    assert_almost_equal(peak_snr(full_scale, adapted), 102.940, 3)
+    assert_almost_equal(norm_brightness_err(full_scale, adapted),
+                        0.0110, 3)
     return data, adapted