diff --git a/tests/test_main.py b/tests/test_main.py
index 52a816e5..524f74e2 100644
--- a/tests/test_main.py
+++ b/tests/test_main.py
@@ -16,7 +16,7 @@ from PIL import Image
 
 import ocrmypdf
 from ocrmypdf._exec import tesseract
-from ocrmypdf.exceptions import ExitCode, MissingDependencyError
+from ocrmypdf.exceptions import ExitCode, MissingDependencyError, OutputFileAccessError
 from ocrmypdf.pdfa import file_claims_pdfa
 from ocrmypdf.pdfinfo import Colorspace, Encoding, PdfInfo
 from ocrmypdf.subprocess import get_version
@@ -239,8 +239,8 @@ def test_german(resources, outdir):
 
 
 def test_klingon(resources, outpdf):
-    p = run_ocrmypdf(resources / 'francais.pdf', outpdf, '-l', 'klz')
-    assert p.returncode == ExitCode.missing_dependency
+    with pytest.raises(MissingDependencyError):
+        run_ocrmypdf_api(resources / 'francais.pdf', outpdf, '-l', 'klz')
 
 
 def test_missing_docinfo(resources, outpdf):
@@ -345,8 +345,8 @@ def test_tesseract_thresholding_invalid(value, resources, no_outpdf):
 
 
 @pytest.mark.parametrize('renderer', RENDERERS)
-def test_tesseract_crash(renderer, resources, no_outpdf):
-    p = run_ocrmypdf(
+def test_tesseract_crash(renderer, resources, no_outpdf, caplog):
+    exitcode = run_ocrmypdf_api(
         resources / 'ccitt.pdf',
         no_outpdf,
         '-v',
@@ -356,24 +356,22 @@ def test_tesseract_crash(renderer, resources, no_outpdf):
         '--plugin',
         'tests/plugins/tesseract_crash.py',
     )
-    assert p.returncode == ExitCode.child_process_error
+    assert exitcode == ExitCode.child_process_error
     assert not no_outpdf.exists()
-    assert "SubprocessOutputError" in p.stderr
+    assert "SubprocessOutputError" in caplog.text
 
 
-def test_tesseract_crash_autorotate(resources, no_outpdf):
-    p = run_ocrmypdf(
+def test_tesseract_crash_autorotate(resources, no_outpdf, caplog):
+    exitcode = run_ocrmypdf_api(
         resources / 'ccitt.pdf',
         no_outpdf,
         '-r',
         '--plugin',
         'tests/plugins/tesseract_crash.py',
     )
-    assert p.returncode == ExitCode.child_process_error
+    assert exitcode == ExitCode.child_process_error
     assert not no_outpdf.exists()
-    assert "uncaught exception" in p.stderr
-    print(p.stdout)
-    print(p.stderr)
+    assert "uncaught exception" in caplog.text
 
 
 @pytest.mark.parametrize('renderer', RENDERERS)
@@ -482,13 +480,13 @@ def protected_file(outdir):
     os.name == 'nt' or os.geteuid() == 0, reason="root can write to anything"
 )
 def test_destination_not_writable(resources, protected_file):
-    p = run_ocrmypdf(
+    exitcode = run_ocrmypdf_api(
         resources / 'jbig2.pdf',
         protected_file,
         '--plugin',
         'tests/plugins/tesseract_noop.py',
     )
-    assert p.returncode == ExitCode.file_access_error, "Expected error"
+    assert exitcode == ExitCode.file_access_error
 
 
 @pytest.fixture
@@ -791,15 +789,18 @@ def test_pdfa_n(pdfa_level, resources, outpdf):
     assert pdfa_info['conformance'] == f'PDF/A-{pdfa_level}B'
 
 
-def test_decompression_bomb_error(resources, outpdf):
-    p = run_ocrmypdf(resources / 'hugemono.pdf', outpdf)
-    assert 'decompression bomb' in p.stderr and '--max-image-mpixels' in p.stderr
+def test_decompression_bomb_error(resources, outpdf, caplog):
+    run_ocrmypdf_api(resources / 'hugemono.pdf', outpdf)
+    assert 'decompression bomb' in caplog.text
+    assert 'max-image-mpixels' in caplog.text
 
 
 @pytest.mark.slow
 def test_decompression_bomb_succeeds(resources, outpdf):
-    p = run_ocrmypdf(resources / 'hugemono.pdf', outpdf, '--max-image-mpixels', '2000')
-    assert p.returncode == 0
+    exitcode = run_ocrmypdf_api(
+        resources / 'hugemono.pdf', outpdf, '--max-image-mpixels', '2000'
+    )
+    assert exitcode == 0
 
 
 def test_text_curves(resources, outpdf):
@@ -829,37 +830,37 @@ def test_text_curves_force(resources, outpdf):
         assert len(info.pages[0].images) != 0, "force did not rasterize"
 
 
-def test_output_is_dir(resources, outdir):
-    p = run_ocrmypdf(
+def test_output_is_dir(resources, outdir, caplog):
+    exitcode = run_ocrmypdf_api(
         resources / 'trivial.pdf',
         outdir,
         '--force-ocr',
         '--plugin',
         'tests/plugins/tesseract_noop.py',
     )
-    assert p.returncode == ExitCode.file_access_error
-    assert 'is not a writable file' in p.stderr
+    assert exitcode == ExitCode.file_access_error
+    assert 'is not a writable file' in caplog.text
 
 
 @pytest.mark.skipif(os.name == 'nt', reason="symlink needs admin permissions")
 def test_output_is_symlink(resources, outdir):
     sym = Path(outdir / 'this_is_a_symlink')
     sym.symlink_to(outdir / 'out.pdf')
-    p = run_ocrmypdf(
+    exitcode = run_ocrmypdf_api(
         resources / 'trivial.pdf',
         sym,
         '--force-ocr',
         '--plugin',
         'tests/plugins/tesseract_noop.py',
     )
-    assert p.returncode == ExitCode.ok, p.stderr
+    assert exitcode == ExitCode.ok
     assert (outdir / 'out.pdf').stat().st_size > 0, 'target file not created'
 
 
-def test_livecycle(resources, no_outpdf):
-    p = run_ocrmypdf(resources / 'livecycle.pdf', no_outpdf)
+def test_livecycle(resources, no_outpdf, caplog):
+    exitcode = run_ocrmypdf_api(resources / 'livecycle.pdf', no_outpdf)
 
-    assert p.returncode == ExitCode.input_file, p.stderr
+    assert exitcode == ExitCode.input_file, caplog.text
 
 
 def test_version_check():
@@ -928,7 +929,7 @@ def test_outputtype_none_bad_setup(resources, outpdf):
 
 
 def test_outputtype_none(resources, outtxt):
-    p = run_ocrmypdf(
+    exitcode = run_ocrmypdf_api(
         resources / 'trivial.pdf',
         '-',
         '--output-type=none',
@@ -937,7 +938,8 @@ def test_outputtype_none(resources, outtxt):
         '--plugin',
         'tests/plugins/tesseract_noop.py',
     )
-    assert p.returncode == ExitCode.ok
+    assert exitcode == ExitCode.ok
+    assert outtxt.exists()
 
 
 @pytest.fixture