TST: Check Error messages

Doing so somethings shows that not the error message you've
expected is thrown, but another one of the same Exception type

Tests/test_basic_features.py

@@ -63,5 +63,6 @@ def test_basic_features():
 
 
 def test_convertToInt():
-    with pytest.raises(PdfReadError):
+    with pytest.raises(PdfReadError) as exc:
         convertToInt(256, 16)
+    assert exc.value.args[0] == "invalid size in convertToInt"

Tests/test_pagerange.py

@@ -44,8 +44,9 @@ def test_str_init(range_str, expected):
 def test_str_init_error():
     init_str = "1-2"
     assert PageRange.valid(init_str) is False
-    with pytest.raises(ParseError):
+    with pytest.raises(ParseError) as exc:
         PageRange(init_str)
+    assert exc.value.args[0] == "1-2"
 
 
 @pytest.mark.parametrize(

Tests/test_reader.py

@@ -194,8 +194,9 @@ def test_get_images_raw(strict, with_prev_0, should_fail):
     )
     pdf_stream = io.BytesIO(pdf_data)
     if should_fail:
-        with pytest.raises(PdfReadError):
+        with pytest.raises(PdfReadError) as exc:
             PdfFileReader(pdf_stream, strict=strict)
+        assert exc.value.args[0] == "/Prev=0 in the trailer (try opening with strict=False)"
     else:
         PdfFileReader(pdf_stream, strict=strict)
 

Tests/test_utils.py

@@ -4,6 +4,7 @@
 import pytest
 
 import PyPDF2.utils
+from PyPDF2.errors import PdfStreamError
 from PyPDF2 import PdfFileReader
 
 TESTS_ROOT = os.path.abspath(os.path.dirname(__file__))
@@ -59,8 +60,9 @@ def test_readUntilRegex_premature_ending_raise():
     import re
 
     stream = io.BytesIO(b"")
-    with pytest.raises(PyPDF2.utils.PdfStreamError):
+    with pytest.raises(PdfStreamError) as exc:
         PyPDF2.utils.readUntilRegex(stream, re.compile(b"."))
+    assert exc.value.args[0] == "Stream has ended unexpectedly"
 
 
 def test_readUntilRegex_premature_ending_name():

Tests/test_writer.py

@@ -26,8 +26,9 @@ def test_writer_operations():
 
     writer = PdfFileWriter()
     page = reader.pages[0]
-    with pytest.raises(PageSizeNotDefinedError):
+    with pytest.raises(PageSizeNotDefinedError) as exc:
         writer.addBlankPage()
+    assert exc.value.args == ()
     writer.insertPage(page, 1)
     writer.removeText()
     writer.insertPage(reader_outline.pages[0], 0)