tests: test TqdmConsole

src/ocrmypdf/api.py

@@ -32,7 +32,15 @@ from .cli import parser
 
 
 class TqdmConsole:
-    """Wrapper to log messages in a way that is compatible with tqdm progress bar"""
+    """Wrapper to log messages in a way that is compatible with tqdm progress bar
+
+    This routes log messages through tqdm so that it can print them above the
+    progress bar, and then refresh the progress bar, rather than overwriting
+    it which looks messy.
+
+    For some reason Python 3.6 prints extra empty messages from time to time,
+    so we suppress those.
+    """
 
     def __init__(self, file):
         self.file = file

tests/test_api.py

@@ -0,0 +1,61 @@
+# © 2019 James R. Barlow: github.com/jbarlow83
+#
+# This file is part of OCRmyPDF.
+#
+# OCRmyPDF is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# OCRmyPDF is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with OCRmyPDF.  If not, see <http://www.gnu.org/licenses/>.
+
+import logging
+from io import StringIO
+
+import pytest
+from tqdm import tqdm
+
+import ocrmypdf
+
+
+def test_raw_console():
+    bio = StringIO()
+    tqconsole = ocrmypdf.api.TqdmConsole(file=bio)
+    tqconsole.write("Test")
+    tqconsole.flush()
+    assert "Test" in bio.getvalue()
+
+
+def test_tqdm_console():
+    log = logging.getLogger()
+    log.setLevel(logging.INFO)
+
+    formatter = logging.Formatter('%(message)s')
+
+    bio = StringIO()
+    console = logging.StreamHandler(ocrmypdf.api.TqdmConsole(file=bio))
+    console.setFormatter(formatter)
+
+    log.addHandler(console)
+
+    def before_pbar(message):
+        # Ensure that log messages appear before the progress bar, even when
+        # printed after the progress bar updates.
+        v = bio.getvalue()
+        pbar_start_marker = '|#'
+        return v.index(message) < v.index(pbar_start_marker)
+
+    with tqdm(total=2, file=bio, disable=False) as pbar:
+        pbar.update()
+        msg = "1/2 above progress bar"
+        log.info(msg)
+        assert before_pbar(msg)
+
+    log.info("done")
+    assert not before_pbar("done")