Implements a new command for fuzzy matching document content and reporting potential duplicates

src/documents/tests/test_management_fuzzy.py

@@ -0,0 +1,97 @@
+from io import StringIO
+
+from django.core.management import CommandError
+from django.core.management import call_command
+from django.test import TestCase
+
+from documents.models import Document
+
+
+class TestFuzzyMatchCommand(TestCase):
+    def call_command(self, *args, **kwargs):
+        stdout = StringIO()
+        stderr = StringIO()
+        call_command(
+            "document_fuzzy_match",
+            *args,
+            stdout=stdout,
+            stderr=stderr,
+            **kwargs,
+        )
+        return stdout.getvalue(), stderr.getvalue()
+
+    def test_invalid_ratio_lower_limit(self):
+        with self.assertRaises(CommandError):
+            self.call_command("--ratio", "-1")
+
+    def test_invalid_ratio_upper_limit(self):
+        with self.assertRaises(CommandError):
+            self.call_command("--ratio", "101")
+
+    def test_no_matches(self):
+        # Content similarity is 82.35
+        Document.objects.create(
+            checksum="BEEFCAFE",
+            title="A",
+            content="first document",
+            mime_type="application/pdf",
+            filename="test.pdf",
+        )
+        Document.objects.create(
+            checksum="DEADBEAF",
+            title="A",
+            content="other first document",
+            mime_type="application/pdf",
+            filename="other_test.pdf",
+        )
+        stdout, _ = self.call_command()
+        self.assertEqual(stdout, "")
+
+    def test_with_matches(self):
+        # Content similarity is 86.667
+        Document.objects.create(
+            checksum="BEEFCAFE",
+            title="A",
+            content="first document scanned by bob",
+            mime_type="application/pdf",
+            filename="test.pdf",
+        )
+        Document.objects.create(
+            checksum="DEADBEAF",
+            title="A",
+            content="first document scanned by alice",
+            mime_type="application/pdf",
+            filename="other_test.pdf",
+        )
+        stdout, _ = self.call_command()
+        self.assertEqual(stdout, "Document 1 fuzzy match to 2 (confidence 86.667)\n")
+
+    def test_with_3_matches(self):
+        # Content similarity is 86.667
+        Document.objects.create(
+            checksum="BEEFCAFE",
+            title="A",
+            content="first document scanned by bob",
+            mime_type="application/pdf",
+            filename="test.pdf",
+        )
+        Document.objects.create(
+            checksum="DEADBEAF",
+            title="A",
+            content="first document scanned by alice",
+            mime_type="application/pdf",
+            filename="other_test.pdf",
+        )
+        Document.objects.create(
+            checksum="CATTLE",
+            title="A",
+            content="first document scanned by pete",
+            mime_type="application/pdf",
+            filename="final_test.pdf",
+        )
+        stdout, _ = self.call_command()
+        lines = [x.strip() for x in stdout.split("\n") if len(x.strip())]
+        self.assertEqual(len(lines), 3)
+        self.assertEqual(lines[0], "Document 1 fuzzy match to 2 (confidence 86.667)")
+        self.assertEqual(lines[1], "Document 1 fuzzy match to 3 (confidence 88.136)")
+        self.assertEqual(lines[2], "Document 2 fuzzy match to 3 (confidence 88.525)")