feat: added tests for avgwordlen function

tests/test_avg_word_len.py

@@ -0,0 +1,35 @@
+import pytest
+from textfeatureinfo.textfeatureinfo import avg_word_len
+
+
+def test_avg_word_len():
+    """
+    Tests the calculation of the average word length from a string.
+    """
+    s1 = ""
+    s2 = "Hello World"
+    s3 = "!!!hello!!!"
+    s4 = "Here.are.some.words."
+    s5 = "Hello, World!"
+
+    assert avg_word_len(s1) == 0, "Output should be 0"
+    assert avg_word_len(s2) == 5, "Output should be 5"
+    assert avg_word_len(s3) == 5, "Output should be 5"
+    assert avg_word_len(s4) == 4, "Output should be 4"
+    assert avg_word_len(s5) == 5, "Output should be 5"
+
+
+def test_avg_word_len_errors():
+    """
+    Checks for TypeErrors when the incorrect argument type is passed into avg_word_len.
+    """
+    with pytest.raises(TypeError):
+        alist = ["a list of words"]
+        avg_word_len(alist)
+
+    with pytest.raises(TypeError):
+        adict = {"a": "dictionary of words"}
+        avg_word_len(adict)
+
+
+test_avg_word_len()