Move tests out to project root. Use absolute import in project

tests/ directory in project root is more standard.
Just had to use absolute path for internal module imports to get it to
work

tests/test_helpers.py

@@ -0,0 +1,30 @@
+from src.utils import helpers
+
+def test_get_from_null_dict():
+    # null handling
+    assert helpers.get_from_dict(dict()) == dict()
+    assert helpers.get_from_dict(dict(), None) == None
+
+    # key present in nested dictionary
+    # 1-level dictionary
+    assert helpers.get_from_dict({'a': 1, 'b': 2}, 'a') == 1
+    assert helpers.get_from_dict({'a': 1, 'b': 2}, 'c') == None
+
+    # 2-level dictionary
+    assert helpers.get_from_dict({'a': {'a_a': 1}, 'b': 2}, 'a') == {'a_a': 1}
+    assert helpers.get_from_dict({'a': {'a_a': 1}, 'b': 2}, 'a', 'a_a') == 1
+
+    # key not present in nested dictionary
+    # 2-level_dictionary
+    assert helpers.get_from_dict({'a': {'a_a': 1}, 'b': 2}, 'b', 'b_a') == None
+
+
+def test_merge_dicts():
+    # basic merge of dicts with non-overlapping keys
+    assert helpers.merge_dicts(priority_dict={'a': 1}, default_dict={'b': 2}) == {'a': 1, 'b': 2}
+
+    # use default dict items when not present in priority dict
+    assert helpers.merge_dicts(priority_dict={}, default_dict={'b': 2}) == {'b': 2}
+
+    # do not override existing key in priority_dict with default dict
+    assert helpers.merge_dicts(priority_dict={'a': 1}, default_dict={'a': 2}) == {'a': 1}