Tighten tolerance to pass tests.

yt/utilities/cosmology.py

@@ -428,7 +428,7 @@ def path_length_function(self, z):
     def path_length(self, z_i, z_f):
         return trapzint(self.path_length_function, z_i, z_f)
 
-    def z_from_t(self, t, tolerance=1e-6):
+    def z_from_t(self, t, tolerance=1e-12):
         """
         Compute the redshift from time after the big bang.
 
@@ -548,6 +548,6 @@ def quan(self):
                 registry = self.unit_registry)
         return self._quan
 
-def trapzint(f, a, b, bins=10000):
+def trapzint(f, a, b, bins=1000):
     zbins = np.logspace(np.log10(a + 1), np.log10(b + 1), bins) - 1
     return np.trapz(f(zbins[:-1]), x=zbins[:-1], dx=np.diff(zbins))