diff --git a/src/gmpy2_mpfr_misc.c b/src/gmpy2_mpfr_misc.c
index 00bf2c9f..13c2eed8 100644
--- a/src/gmpy2_mpfr_misc.c
+++ b/src/gmpy2_mpfr_misc.c
@@ -448,9 +448,11 @@ GMPy_MPFR_Integer_Ratio_Method(PyObject *self, PyObject *args)
     num = GMPy_MPZ_New(context);
     den = GMPy_MPZ_New(context);
     if (!num || !den) {
+        /* LCOV_EXCL_START */
         Py_XDECREF((PyObject*)num);
         Py_XDECREF((PyObject*)den);
         return NULL;
+        /* LCOV_EXCL_STOP */
     }
 
     if (mpfr_zero_p(MPFR(self))) {
@@ -472,8 +474,10 @@ GMPy_MPFR_Integer_Ratio_Method(PyObject *self, PyObject *args)
     }
     result = Py_BuildValue("(NN)", (PyObject*)num, (PyObject*)den);
     if (!result) {
+        /* LCOV_EXCL_START */
         Py_DECREF((PyObject*)num);
         Py_DECREF((PyObject*)den);
+        /* LCOV_EXCL_STOP */
     }
     return result;
 }
@@ -505,9 +509,11 @@ GMPy_MPFR_Mantissa_Exp_Method(PyObject *self, PyObject *args)
     mantissa = GMPy_MPZ_New(context);
     exponent = GMPy_MPZ_New(context);
     if (!mantissa || !exponent) {
+        /* LCOV_EXCL_START */
         Py_XDECREF((PyObject*)mantissa);
         Py_XDECREF((PyObject*)exponent);
         return NULL;
+        /* LCOV_EXCL_STOP */
     }
 
     if (mpfr_zero_p(MPFR(self))) {
@@ -520,8 +526,10 @@ GMPy_MPFR_Mantissa_Exp_Method(PyObject *self, PyObject *args)
     }
     result = Py_BuildValue("(NN)", (PyObject*)mantissa, (PyObject*)exponent);
     if (!result) {
+        /* LCOV_EXCL_START */
         Py_DECREF((PyObject*)mantissa);
         Py_DECREF((PyObject*)exponent);
+        /* LCOV_EXCL_STOP */
     }
     return result;
 }
diff --git a/test/test_functions.py b/test/test_functions.py
index 16bd9db9..19492246 100644
--- a/test/test_functions.py
+++ b/test/test_functions.py
@@ -1,8 +1,9 @@
 import pytest
 
 import gmpy2
-from gmpy2 import (root, rootn, zero, mpz, mpq, mpfr, mpc, is_nan, maxnum,
-                   minnum, fma, fms, ieee, fmma, fmms)
+from gmpy2 import (can_round, fac, fma, fmma, fmms, fms, get_exp, ieee, is_nan,
+                   maxnum, minnum, mpc, mpfr, mpq, mpz, root, rootn, set_exp,
+                   zero)
 
 
 def test_root():
@@ -133,3 +134,35 @@ def test_trigonometric():
     assert gmpy2.atanh(mpc(2.0, 3.0)) == gmpy2.atanh(complex(2, 3))
 
     assert gmpy2.tanh(mpc(4,5)) == mpc('1.0005630461157933-0.00036520305451130409j')
+
+
+def test_get_exp():
+    ctx = gmpy2.get_context()
+    ctx.trap_erange = True
+
+    pytest.raises(gmpy2.RangeError, lambda: get_exp(mpfr('inf')))
+
+
+def test_set_exp():
+    pytest.raises(ValueError, lambda: set_exp(mpfr('1.0'), int(fac(100))))
+
+    gmpy2.set_context(gmpy2.ieee(32))
+    ctx = gmpy2.get_context()
+    ctx.trap_erange = True
+
+    pytest.raises(gmpy2.RangeError, lambda: set_exp(mpfr('1.0'), 1000))
+
+    ctx.trap_erange = False
+    assert set_exp(mpfr('1.0'), 1000) == mpfr('1.0')
+
+
+def test_can_round():
+    pytest.raises(TypeError, lambda: can_round(mpfr('1.1'), 10, "spam"))
+    pytest.raises(ValueError, lambda: can_round(mpfr('1.1'), 10, 111, 111, 111))
+    pytest.raises(ValueError, lambda: can_round(mpfr('1.1'), 10, 1, 111, 111))
+    pytest.raises(ValueError, lambda: can_round(mpfr('1.1'), 10, 1, 1, -111))
+
+    x = mpfr('-1.112')
+
+    assert can_round(x, 10, 1, 1, 1)
+    assert not can_round(x, 10, 1, 1, 10)
diff --git a/test/test_misc.py b/test/test_misc.py
index c335e5c3..c60aa185 100644
--- a/test/test_misc.py
+++ b/test/test_misc.py
@@ -1,3 +1,5 @@
+import sys
+
 import gmpy2
 
 
@@ -13,3 +15,7 @@ def test_misc():
                                '3 or later. The supported versions of the GMP, '
                                'MPFR, and MPC libraries are also licensed '
                                'under LGPL 3 or later.')
+
+
+def test_sizeof():
+    assert sys.getsizeof(gmpy2.mpfr('1.0')) > 0
diff --git a/test/test_mpfr.py b/test/test_mpfr.py
index 6bee22fe..245db419 100644
--- a/test/test_mpfr.py
+++ b/test/test_mpfr.py
@@ -288,3 +288,16 @@ def fmt(v):
     assert fmt(gmpy2.next_toward(a, 10)) == '1.00000000000000000000001p-126'
 
     gmpy2.set_context(gmpy2.context())
+
+
+def test_mpfr_as_integer_ratio():
+    assert mpfr('1.1e+2').as_integer_ratio() == (mpz(110), mpz(1))
+
+
+def test_mpfr_round():
+    pytest.raises(TypeError, lambda: round(mpfr('1.0'), "spam"))
+
+    r = round(mpfr('-0.0'), 123)
+    assert r.is_zero() and r.is_signed()
+
+    assert round(mpfr('12.34'), -1) == mpfr('10.0')