Make ghostscript default backend and add support for string keywords

tests/test_errors.py

@@ -32,56 +32,6 @@ def test_unsupported_format():
         tables = camelot.read_pdf(filename)
 
 
-def test_stream_equal_length():
-    message = "Length of table_areas and columns" " should be equal"
-    with pytest.raises(ValueError, match=message):
-        tables = camelot.read_pdf(
-            filename,
-            flavor="stream",
-            table_areas=["10,20,30,40"],
-            columns=["10,20,30,40", "10,20,30,40"],
-        )
-
-
-def test_image_warning():
-    filename = os.path.join(testdir, "image.pdf")
-    with warnings.catch_warnings():
-        warnings.simplefilter("error")
-        with pytest.raises(UserWarning) as e:
-            tables = camelot.read_pdf(filename)
-            assert (
-                str(e.value)
-                == "page-1 is image-based, camelot only works on text-based pages."
-            )
-
-
-def test_lattice_no_tables_on_page():
-    filename = os.path.join(testdir, "empty.pdf")
-    with warnings.catch_warnings():
-        warnings.simplefilter("error")
-        with pytest.raises(UserWarning) as e:
-            tables = camelot.read_pdf(filename, flavor="lattice")
-        assert str(e.value) == "No tables found on page-1"
-
-
-def test_stream_no_tables_on_page():
-    filename = os.path.join(testdir, "empty.pdf")
-    with warnings.catch_warnings():
-        warnings.simplefilter("error")
-        with pytest.raises(UserWarning) as e:
-            tables = camelot.read_pdf(filename, flavor="stream")
-        assert str(e.value) == "No tables found on page-1"
-
-
-def test_stream_no_tables_in_area():
-    filename = os.path.join(testdir, "only_page_number.pdf")
-    with warnings.catch_warnings():
-        warnings.simplefilter("error")
-        with pytest.raises(UserWarning) as e:
-            tables = camelot.read_pdf(filename, flavor="stream")
-        assert str(e.value) == "No tables found in table area 1"
-
-
 def test_no_tables_found_logs_suppressed():
     filename = os.path.join(testdir, "foo.pdf")
     with warnings.catch_warnings():
@@ -118,3 +68,68 @@ def test_bad_password():
     message = "file has not been decrypted"
     with pytest.raises(Exception, match=message):
         tables = camelot.read_pdf(filename, password="wrongpass")
+
+
+def test_stream_equal_length():
+    message = "Length of table_areas and columns" " should be equal"
+    with pytest.raises(ValueError, match=message):
+        tables = camelot.read_pdf(
+            filename,
+            flavor="stream",
+            table_areas=["10,20,30,40"],
+            columns=["10,20,30,40", "10,20,30,40"],
+        )
+
+
+def test_image_warning():
+    filename = os.path.join(testdir, "image.pdf")
+    with warnings.catch_warnings():
+        warnings.simplefilter("error")
+        with pytest.raises(UserWarning) as e:
+            tables = camelot.read_pdf(filename)
+            assert (
+                str(e.value)
+                == "page-1 is image-based, camelot only works on text-based pages."
+            )
+
+
+def test_stream_no_tables_on_page():
+    filename = os.path.join(testdir, "empty.pdf")
+    with warnings.catch_warnings():
+        warnings.simplefilter("error")
+        with pytest.raises(UserWarning) as e:
+            tables = camelot.read_pdf(filename, flavor="stream")
+        assert str(e.value) == "No tables found on page-1"
+
+
+def test_stream_no_tables_in_area():
+    filename = os.path.join(testdir, "only_page_number.pdf")
+    with warnings.catch_warnings():
+        warnings.simplefilter("error")
+        with pytest.raises(UserWarning) as e:
+            tables = camelot.read_pdf(filename, flavor="stream")
+        assert str(e.value) == "No tables found in table area 1"
+
+
+def test_lattice_no_tables_on_page():
+    filename = os.path.join(testdir, "empty.pdf")
+    with warnings.catch_warnings():
+        warnings.simplefilter("error")
+        with pytest.raises(UserWarning) as e:
+            tables = camelot.read_pdf(filename, flavor="lattice")
+        assert str(e.value) == "No tables found on page-1"
+
+
+def test_lattice_unknown_backend():
+    message = "Unknown backend 'mupdf' specified. Please use either 'poppler' or 'ghostscript'."
+    with pytest.raises(NotImplementedError, match=message):
+        tables = camelot.read_pdf(filename, backend="mupdf")
+
+
+def test_lattice_no_convert_method():
+    class ConversionBackend(object):
+        pass
+
+    message = "must implement a 'convert' method"
+    with pytest.raises(NotImplementedError, match=message):
+        tables = camelot.read_pdf(filename, backend=ConversionBackend())

tests/test_image_conversion_backend.py

@@ -4,18 +4,16 @@ import pytest
 
 import camelot.backends.image_conversion
 from camelot.backends import ImageConversionBackend
-from camelot.backends.poppler_backend import PopplerBackend
-from camelot.backends.ghostscript_backend import  GhostscriptBackend
 
 
 class PopplerBackendError(object):
     def convert(self, pdf_path, png_path):
-        raise ValueError('conversion failed')
+        raise ValueError("Image conversion failed")
 
 
 class GhostscriptBackendError(object):
     def convert(self, pdf_path, png_path):
-        raise ValueError('conversion failed')
+        raise ValueError("Image conversion failed")
 
 
 class GhostscriptBackendNoError(object):
@@ -24,26 +22,39 @@ class GhostscriptBackendNoError(object):
 
 
 def test_poppler_backend_error_when_no_use_fallback(monkeypatch):
-    backends = {"poppler": PopplerBackendError, "ghostscript": GhostscriptBackendNoError}
-    monkeypatch.setattr("camelot.backends.image_conversion.backends", backends, raising=True)
+    BACKENDS = {
+        "poppler": PopplerBackendError,
+        "ghostscript": GhostscriptBackendNoError,
+    }
+    monkeypatch.setattr(
+        "camelot.backends.image_conversion.BACKENDS", BACKENDS, raising=True
+    )
     backend = ImageConversionBackend(use_fallback=False)
 
-    message = "conversion failed with image conversion backend 'poppler'"
+    message = "Image conversion failed with image conversion backend 'poppler'"
     with pytest.raises(ValueError, match=message):
-        backend.convert('foo', 'bar')
+        backend.convert("foo", "bar")
+
 
 def test_ghostscript_backend_when_use_fallback(monkeypatch):
-    backends = {"poppler": PopplerBackendError, "ghostscript": GhostscriptBackendNoError}
-    monkeypatch.setattr("camelot.backends.image_conversion.backends", backends, raising=True)
+    BACKENDS = {
+        "poppler": PopplerBackendError,
+        "ghostscript": GhostscriptBackendNoError,
+    }
+    monkeypatch.setattr(
+        "camelot.backends.image_conversion.BACKENDS", BACKENDS, raising=True
+    )
     backend = ImageConversionBackend()
-    backend.convert('foo', 'bar')
+    backend.convert("foo", "bar")
 
 
 def test_ghostscript_backend_error_when_use_fallback(monkeypatch):
-    backends = {"poppler": PopplerBackendError, "ghostscript": GhostscriptBackendError}
-    monkeypatch.setattr("camelot.backends.image_conversion.backends", backends, raising=True)
+    BACKENDS = {"poppler": PopplerBackendError, "ghostscript": GhostscriptBackendError}
+    monkeypatch.setattr(
+        "camelot.backends.image_conversion.BACKENDS", BACKENDS, raising=True
+    )
     backend = ImageConversionBackend()
 
-    message = "conversion failed with image conversion backend 'ghostscript'"
+    message = "Image conversion failed with image conversion backend 'ghostscript'"
     with pytest.raises(ValueError, match=message):
-        backend.convert('foo', 'bar')
+        backend.convert("foo", "bar")

tests/test_plotting.py

@@ -6,9 +6,6 @@ import sys
 import pytest
 
 import camelot
-from camelot.backends.poppler_backend import PopplerBackend
-from camelot.backends.ghostscript_backend import GhostscriptBackend
-
 
 testdir = os.path.dirname(os.path.abspath(__file__))
 testdir = os.path.join(testdir, "files")
@@ -31,7 +28,7 @@ def test_textedge_plot():
 @pytest.mark.mpl_image_compare(baseline_dir="files/baseline_plots", remove_text=True)
 def test_lattice_contour_plot_poppler():
     filename = os.path.join(testdir, "foo.pdf")
-    tables = camelot.read_pdf(filename, backend=PopplerBackend())
+    tables = camelot.read_pdf(filename, backend="poppler")
     return camelot.plot(tables[0], kind="contour")
 
 
@@ -41,7 +38,7 @@ def test_lattice_contour_plot_ghostscript():
         pytest.skip("Skipping ghostscript test on Windows")
 
     filename = os.path.join(testdir, "foo.pdf")
-    tables = camelot.read_pdf(filename, backend=GhostscriptBackend())
+    tables = camelot.read_pdf(filename, backend="ghostscript")
     return camelot.plot(tables[0], kind="contour")
 
 
@@ -55,7 +52,7 @@ def test_stream_contour_plot():
 @pytest.mark.mpl_image_compare(baseline_dir="files/baseline_plots", remove_text=True)
 def test_line_plot_poppler():
     filename = os.path.join(testdir, "foo.pdf")
-    tables = camelot.read_pdf(filename, backend=PopplerBackend())
+    tables = camelot.read_pdf(filename, backend="poppler")
     return camelot.plot(tables[0], kind="line")
 
 
@@ -65,14 +62,14 @@ def test_line_plot_ghostscript():
         pytest.skip("Skipping ghostscript test on Windows")
 
     filename = os.path.join(testdir, "foo.pdf")
-    tables = camelot.read_pdf(filename, backend=GhostscriptBackend())
+    tables = camelot.read_pdf(filename, backend="ghostscript")
     return camelot.plot(tables[0], kind="line")
 
 
 @pytest.mark.mpl_image_compare(baseline_dir="files/baseline_plots", remove_text=True)
 def test_joint_plot_poppler():
     filename = os.path.join(testdir, "foo.pdf")
-    tables = camelot.read_pdf(filename, backend=PopplerBackend())
+    tables = camelot.read_pdf(filename, backend="poppler")
     return camelot.plot(tables[0], kind="joint")
 
 
@@ -82,14 +79,14 @@ def test_joint_plot_ghostscript():
         pytest.skip("Skipping ghostscript test on Windows")
 
     filename = os.path.join(testdir, "foo.pdf")
-    tables = camelot.read_pdf(filename, backend=GhostscriptBackend())
+    tables = camelot.read_pdf(filename, backend="ghostscript")
     return camelot.plot(tables[0], kind="joint")
 
 
 @pytest.mark.mpl_image_compare(baseline_dir="files/baseline_plots", remove_text=True)
 def test_grid_plot_poppler():
     filename = os.path.join(testdir, "foo.pdf")
-    tables = camelot.read_pdf(filename, backend=PopplerBackend())
+    tables = camelot.read_pdf(filename, backend="poppler")
     return camelot.plot(tables[0], kind="grid")
 
 
@@ -99,5 +96,5 @@ def test_grid_plot_ghostscript():
         pytest.skip("Skipping ghostscript test on Windows")
 
     filename = os.path.join(testdir, "foo.pdf")
-    tables = camelot.read_pdf(filename, backend=GhostscriptBackend())
+    tables = camelot.read_pdf(filename, backend="ghostscript")
     return camelot.plot(tables[0], kind="grid")