Add test for parsing empty string operands

pash_annotations/parser/tests/test_parser_empty_str.py

@@ -0,0 +1,23 @@
+'''This is solely to test whether commands with the empty string as an operand
+such as echo "" function properly'''
+
+from pash_annotations.datatypes.CommandInvocationInitial import CommandInvocationInitial
+from pash_annotations.parser.parser import parse
+
+def test_empty_str_1():
+    parser_result = parse('echo ""')
+
+    args = []
+    operands = []
+    expected_result = CommandInvocationInitial("echo", args, operands)
+
+    assert expected_result == parser_result
+
+def test_empty_str_2():
+    parser_result = parse('cat ""')
+
+    args = []
+    operands = []
+    expected_result = CommandInvocationInitial("cat", args, operands)
+
+    assert expected_result == parser_result