Add tests for line merging logic

tests/builders/test_line_builder.py

@@ -0,0 +1,24 @@
+import pytest
+
+from marker.schema import BlockTypes
+
+# Page contains provider lines that are longer than detected lines
+# Any bad merging will cause broken final OCR results with format lines
+@pytest.mark.filename("mixed_eng_hindi.pdf")
+@pytest.mark.config({"page_range": [2], "format_lines": True})
+def test_provider_detected_line_merge(pdf_document):
+    page = pdf_document.pages[0]
+    text_lines = page.contained_blocks(pdf_document, (BlockTypes.Line,))
+
+    # This count includes detected lines merged in with provider lines
+    assert len(text_lines) == 83
+
+# Page provider lines only contain english, while the hindi is missing
+# format_lines should fill in the missing lines
+@pytest.mark.filename("mixed_eng_hindi.pdf")
+@pytest.mark.config({"page_range": [0], "format_lines": True})
+def test_fill_missing_provider_lines(pdf_document):
+    page = pdf_document.pages[0]
+    raw_text = page.raw_text(pdf_document)
+    assert "प्राधिकार से प्रकाशित" in raw_text
+    assert "खान मंत्रालय" in raw_text