diff --git a/centerline_width/pytests/test_verifyPreprocessing.py b/centerline_width/pytests/test_verifyPreprocessing.py
index cda3890..a75724f 100644
--- a/centerline_width/pytests/test_verifyPreprocessing.py
+++ b/centerline_width/pytests/test_verifyPreprocessing.py
@@ -1,34 +1,87 @@
 # centerline-width/: python -m pytest -v
 # Pytests to Compare and Verify Expected Outputs
-from io import StringIO
 import re
 
 # External Python libraries (installed via pip install)
 import pytest
+import pandas as pd
 
 # Internal centerline-width reference to access functions, global variables, and error handling
 import centerline_width
 
 
-def test_preprocessing_emptyRightBankCSV():
+@pytest.fixture(scope="function")
+def generate_txt_convertColumnsToCSV_noFlip(tmpdir):
+    temp_text_file = tmpdir.join("pytest.txt")
+    with open(str(temp_text_file), "w") as text_file:
+        text_file.write("llat,llon,rlat,rlon\n")
+        text_file.write("30.037581,-92.868569,30.037441,-92.867476\n")
+        text_file.write("30.137581,-92.868569,30.037441,-92.867476\n")
+        text_file.write("30.237581,-92.868569,30.037441,-92.867476\n")
+    centerline_width.convertColumnsToCSV(text_file=str(temp_text_file),
+                                         flipBankDirection=False)
+
+    return temp_text_file
+
+
+def test_txt_convertColumnsToCSV(generate_txt_convertColumnsToCSV_noFlip):
+    expected_df = pd.DataFrame({
+        'llat': [30.037581, 30.137581, 30.237581],
+        'llon': [-92.868569, -92.868569, -92.868569],
+        'rlat': [30.037441, 30.037441, 30.037441],
+        'rlon': [-92.867476, -92.867476, -92.867476]
+    })
+    txt_output_df = pd.read_csv(generate_txt_convertColumnsToCSV_noFlip)
+    assert expected_df.columns.tolist() == txt_output_df.columns.tolist()
+    assert list(expected_df["llat"]) == list(txt_output_df["llat"])
+    assert list(expected_df["llon"]) == list(txt_output_df["llon"])
+    assert list(expected_df["rlat"]) == list(txt_output_df["rlat"])
+    assert list(expected_df["rlon"]) == list(txt_output_df["rlon"])
+
+
+@pytest.fixture(scope="function")
+def generate_txt_convertColumnsToCSV_emptyRight(tmpdir):
+    temp_text_file = tmpdir.join("pytest.txt")
+    with open(str(temp_text_file), "w") as text_file:
+        text_file.write("llat,llon,rlat,rlon\n")
+        text_file.write("30.037581,-92.868569,,\n")
+        text_file.write("30.137581,-92.868569,,\n")
+        text_file.write("30.237581,-92.868569,,\n")
+    centerline_width.convertColumnsToCSV(text_file=str(temp_text_file),
+                                         flipBankDirection=False)
+
+    return temp_text_file
+
+
+def test_preprocessing_emptyRightBankCSV(
+        generate_txt_convertColumnsToCSV_emptyRight):
     with pytest.raises(
             ValueError,
             match=re.escape(
                 "CRITICAL ERROR, right bank data is empty (or NaN)")):
-        csv_example = StringIO()
-        csv_example.write("llat,llon,rlat,rlon\n")
-        csv_example.write("30.037581,-92.868569,,\n")
-        csv_example.seek(0)
-        centerline_width.riverCenterline(csv_data=csv_example)
+        centerline_width.riverCenterline(
+            csv_data=str(generate_txt_convertColumnsToCSV_emptyRight))
+
+
+@pytest.fixture(scope="function")
+def generate_txt_convertColumnsToCSV_emptyLeft(tmpdir):
+    temp_text_file = tmpdir.join("pytest.txt")
+    with open(str(temp_text_file), "w") as text_file:
+        text_file.write("llat,llon,rlat,rlon\n")
+        text_file.write(",,30.037441,-92.867476\n")
+        text_file.write(",,30.037441,-92.867476\n")
+        text_file.write(",,30.037441,-92.867476\n")
+    centerline_width.convertColumnsToCSV(text_file=str(temp_text_file),
+                                         flipBankDirection=False)
+
+    return temp_text_file
 
 
-def test_preprocessing_emptyLeftBankCSV():
+def test_preprocessing_emptyLeftBankCSV(
+        generate_txt_convertColumnsToCSV_emptyLeft):
     with pytest.raises(
             ValueError,
             match=re.escape(
                 "CRITICAL ERROR, left bank data is empty (or NaN)")):
-        csv_example = StringIO()
-        csv_example.write("llat,llon,rlat,rlon\n")
-        csv_example.write(",,30.037441,-92.867476\n")
-        csv_example.seek(0)
-        centerline_width.riverCenterline(csv_data=csv_example)
+        centerline_width.riverCenterline(
+            csv_data=str(generate_txt_convertColumnsToCSV_emptyLeft))