Adjust tests to actually do something

python setup.py test is a noop. Upstream is using nosetests to run
tests under travis. Do the same here.

python-freezegun.spec

@@ -12,7 +12,7 @@
 
 Name:               python-freezegun
 Version:            0.1.12
-Release:            3%{?dist}
+Release:            4%{?dist}
 Summary:            Let your Python tests travel through time
 
 Group:              Development/Libraries
@@ -30,6 +30,9 @@ BuildRequires:      python-setuptools
 BuildRequires:      python-six
 BuildRequires:      python-dateutil
 BuildRequires:      python-sure
+BuildRequires:      python-nose
+BuildRequires:      python-coverage
+BuildRequires:      python-mock
 
 %if 0%{?with_python3}
 BuildRequires:      python3-devel
@@ -37,6 +40,9 @@ BuildRequires:      python3-setuptools
 BuildRequires:      python3-six
 BuildRequires:      python3-dateutil
 BuildRequires:      python3-sure
+BuildRequires:      python3-nose
+BuildRequires:      python3-coverage
+BuildRequires:      python3-mock
 %endif
 
 Requires:           python-six
@@ -87,13 +93,14 @@ popd
 %{__python2} setup.py install -O1 --skip-build --root=%{buildroot}
 
 %check
-%{__python2} setup.py test
-%if 0%{?with_python3}
+%if %with python3
 pushd %{py3dir}
-%{__python3} setup.py test
+nosetests-%{python3_version} tests/
 popd
 %endif
 
+nosetests-%{python2_version} tests/
+
 %files
 %doc README.rst LICENSE
 %{python2_sitelib}/%{modname}/
@@ -107,6 +114,9 @@ popd
 %endif
 
 %changelog
+* Thu Jan 22 2015 Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl> - 0.1.12-4
+- Adjust tests to actually do something
+
 * Sat Jun 07 2014 Fedora Release Engineering <rel-eng@lists.fedoraproject.org> - 0.1.12-3
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_21_Mass_Rebuild