Add final bits of test coverage

Added weak tests for a couple of hard-to-test visual debugging methods
in display.py.

Also marked an exception-handling block in pdf.py as `pragma: nocover`
because we don't yet have a PDF to test it with, but the logic there is
simple and straightforward.

CHANGELOG.md

@@ -8,6 +8,7 @@ All notable changes to this project will be documented in this file. The format
 
 - Add type annotations, and refactor parts of the library accordingly.
 - Add enforcement of type annotations via `mypy --strict`.
+- Add final bits of test coverage.
 - Add `TableSettings` class, a behind-the-scenes handler for managing and validating table-extraction settings.
 
 ### Changed

pdfplumber/display.py

@@ -10,7 +10,7 @@
 from ._typing import T_bbox, T_num, T_obj, T_obj_list, T_point, T_seq
 from .table import T_table_settings, Table, TableFinder, TableSettings
 
-if TYPE_CHECKING:
+if TYPE_CHECKING:  # pragma: nocover
     from pandas.core.frame import DataFrame
     from pandas.core.series import Series
 

pdfplumber/pdf.py

@@ -46,7 +46,7 @@ def __init__(
         for k, v in self.metadata.items():
             try:
                 self.metadata[k] = resolve_and_decode(v)
-            except Exception as e:
+            except Exception as e:  # pragma: nocover
                 if strict_metadata:
                     # Raise an exception since unable to resolve the metadata value.
                     raise

tests/test_display.py

@@ -4,7 +4,10 @@
 import os
 import unittest
 
+import pytest
+
 import pdfplumber
+from pdfplumber.table import TableFinder
 
 logging.disable(logging.ERROR)
 
@@ -34,6 +37,11 @@ def test_debug_tablefinder(self):
         self.im.reset()
         settings = {"horizontal_strategy": "text", "intersection_tolerance": 5}
         self.im.debug_tablefinder(settings)
+        finder = TableFinder(self.im.page, settings)
+        self.im.debug_tablefinder(finder)
+
+        with pytest.raises(ValueError):
+            self.im.debug_tablefinder(0)
 
     def test_bytes_stream_to_image(self):
         path = os.path.join(HERE, "pdfs/nics-background-checks-2015-11.pdf")
@@ -52,3 +60,20 @@ def test_cropped(self):
 
     def test_copy(self):
         assert self.im.copy().original == self.im.original
+
+    def test_outline_words(self):
+        self.im.outline_words(
+            stroke="blue",
+            fill=(0, 200, 10),
+            stroke_width=2,
+            x_tolerance=5,
+            y_tolerance=5,
+        )
+
+    def test_outline_chars(self):
+        self.im.outline_chars(stroke="blue", fill=(0, 200, 10), stroke_width=2)
+
+    def test__repr_png_(self):
+        png = self.im._repr_png_()
+        assert isinstance(png, bytes)
+        assert len(png) == 71948