[Tests] Refactored tests with Pytest.

.gitignore

@@ -1,4 +1,5 @@
 __pycache__/*
 plume.egg-info/*
+.cache/*
 *.pyc
 *.db

tests/test_clause.py

@@ -0,0 +1,45 @@
+import plume
+from tests.utils import Pokemon
+
+import pytest
+
+
+class TestClause:
+
+    def test_allows_or_operator_between_two_clauses(self):
+        result = str((Pokemon.name == 'Charamander') | (Pokemon.name == 'Bulbasaur'))
+        expected = "( name = 'Charamander' OR name = 'Bulbasaur' )"
+        assert result == expected
+
+    def test_or_operator_between_two_clauses_add_brackets(self):
+        result = str((Pokemon.name == 'Charamander') | (Pokemon.name == 'Bulbasaur'))
+        expected_open_bracket = '('
+        expected_close_bracket = ')'
+        assert result[0] == expected_open_bracket
+        assert result[-1] == expected_close_bracket
+
+    def test_allows_and_operator_between_two_clauses(self):
+        result = str((Pokemon.name == 'Charamander') & (Pokemon.level == 18))
+        expected = "name = 'Charamander' AND level = 18"
+        assert result == expected
+
+    def test_and_operator_between_two_clauses_does_not_add_brackets(self):
+        result = str((Pokemon.name == 'Charamander') & (Pokemon.level == 18))
+        assert result[0] != '('
+        assert result[-1] != ')'
+
+    def test_or_operator_has_lower_precedence_than_and_operator(self):
+        result = str(
+            (Pokemon.name == 'Charamander') | (Pokemon.name == 'Bulbasaur')
+            & (Pokemon.level > 18)
+        )
+        expected = "( name = 'Charamander' OR name = 'Bulbasaur' AND level > 18 )"
+        assert result == expected
+
+    def test_bracket_has_higher_precedence_than_and_operator(self):
+        result = str(
+            ((Pokemon.name == 'Charamander') | (Pokemon.name == 'Bulbasaur'))
+            & (Pokemon.level > 18)
+        )
+        expected = "level > 18 AND ( name = 'Charamander' OR name = 'Bulbasaur' )"
+        assert result == expected