Merge pull request #6 from ajschofield/feat/read_s3

implement reading from s3 bucket

1 files changed, 142 insertions, 1 deletions

diff --git a/test/test_csv_reader.py b/test/test_csv_reader.py
index af13cff..e4c135b 100644
--- a/test/test_csv_reader.py
+++ b/test/test_csv_reader.py
@@ -1,10 +1,15 @@
-# csv_reader.py - tests
+# csv_reader.py - tests for read_string and read_s3
 # Author: Alex Schofield
 
+import boto3
+from moto import mock_aws
 from obfuscator.csv_reader import CSVReader
+import pytest
 
 reader = CSVReader()
 
+# CSVREADER: READ_STRING TESTS
+
 # Check if the function can read a CSV string with no content and return
 # an empty list
 
@@ -61,3 +66,139 @@ def test_csv_with_quoted_fields_should_run_as_expected():
         {"student_id": "5678", "name": "Student 2", "course": "Course 2"},
     ]
     assert result == expected
+
+
+# CSVREADER: READ_S3 TESTS
+
+
+def setup_s3(s3_client, bucket: str, key: str, content: str):
+    s3_client.create_bucket(
+        Bucket=bucket,
+        CreateBucketConfiguration={"LocationConstraint": "eu-west-2"},
+    )
+    s3_client.put_object(Bucket=bucket, Key=key, Body=content)
+
+
+@pytest.fixture(autouse=True)
+def s3_client():
+    with mock_aws():
+        yield boto3.client("s3", "eu-west-2")
+
+
+def test_read_s3_valid_csv_returns_expected():
+    with mock_aws():
+        s3 = boto3.client("s3", region_name="eu-west-2")
+        bucket = "test-bucket"
+        key = "data/mock.csv"
+
+        csv_content = (
+            "student_id,name,course\n"
+            "1234,Student 1,Course 1\n"
+            "5678,Student 2,Course 2\n"
+        )
+
+        setup_s3(s3, bucket, key, csv_content)
+        path = f"s3://{bucket}/{key}"
+
+        data = reader.read_s3(path)
+
+        expected = [
+            {"student_id": "1234", "name": "Student 1", "course": "Course 1"},
+            {"student_id": "5678", "name": "Student 2", "course": "Course 2"},
+        ]
+
+        assert data == expected
+
+
+def test_read_s3_empty_csv_returns_empty_list():
+    with mock_aws():
+        s3 = boto3.client("s3", region_name="eu-west-2")
+        bucket = "empty-bucket"
+        key = "data/empty.csv"
+        csv_content = "student_id,name,course\n"
+        setup_s3(s3, bucket, key, csv_content)
+        path = f"s3://{bucket}/{key}"
+
+        data = CSVReader.read_s3(path)
+        assert data == []
+
+
+def test_read_s3_nonexistent_bucket_raises_exception():
+    with mock_aws():
+        bucket = "nonexistent-bucket"
+        key = "data/mock.csv"
+        path = f"s3://{bucket}/{key}"
+        with pytest.raises(Exception):
+            CSVReader.read_s3(path)
+
+
+def test_read_s3_nonexistent_key_raises_exception():
+    with mock_aws():
+        s3 = boto3.client("s3", region_name="eu-west-2")
+        bucket = "test-bucket"
+        s3.create_bucket(
+            Bucket=bucket,
+            CreateBucketConfiguration={"LocationConstraint": "eu-west-2"},
+        )
+        key = "data/nonexistent.csv"
+        path = f"s3://{bucket}/{key}"
+        with pytest.raises(Exception):
+            CSVReader.read_s3(path)
+
+
+def test_read_s3_malformed_csv_returns_expected():
+    with mock_aws():
+        s3 = boto3.client("s3", region_name="eu-west-2")
+        bucket = "test-bucket"
+        key = "data/malformed.csv"
+        csv_content = "1234,Student 1,Course 1\n" "5678,Student 2,Course 2\n"
+        setup_s3(s3, bucket, key, csv_content)
+        path = f"s3://{bucket}/{key}"
+
+        data = CSVReader.read_s3(path)
+        expected = [{"1234": "5678", "Student 1": "Student 2", "Course 1": "Course 2"}]
+        assert data == expected
+
+
+def test_read_s3_csv_with_extra_empty_lines():
+    with mock_aws():
+        s3 = boto3.client("s3", region_name="eu-west-2")
+        bucket = "test-bucket"
+        key = "data/extra_lines.csv"
+        csv_content = (
+            "student_id,name,course\n"
+            "1234,Student 1,Course 1\n"
+            "\n"
+            "5678,Student 2,Course 2\n"
+            "\n"
+        )
+        setup_s3(s3, bucket, key, csv_content)
+        path = f"s3://{bucket}/{key}"
+
+        data = CSVReader.read_s3(path)
+        expected = [
+            {"student_id": "1234", "name": "Student 1", "course": "Course 1"},
+            {"student_id": "5678", "name": "Student 2", "course": "Course 2"},
+        ]
+        assert data == expected
+
+
+def test_read_s3_csv_with_whitespace_in_fields():
+    with mock_aws():
+        s3 = boto3.client("s3", region_name="eu-west-2")
+        bucket = "test-bucket"
+        key = "data/whitespace.csv"
+        csv_content = (
+            "student_id, name , course \n"
+            " 1234 , Student 1 , Course 1 \n"
+            "5678,Student 2,Course 2\n"
+        )
+        setup_s3(s3, bucket, key, csv_content)
+        path = f"s3://{bucket}/{key}"
+
+        data = CSVReader.read_s3(path)
+        expected = [
+            {"student_id": " 1234 ", " name ": " Student 1 ", " course ": " Course 1 "},
+            {"student_id": "5678", " name ": "Student 2", " course ": "Course 2"},
+        ]
+        assert data == expected