diff --git a/test/fixtures/project_b/README.rst b/test/fixtures/project_b/README.rst
index e69de29..47c02e9 100644
--- a/test/fixtures/project_b/README.rst
+++ b/test/fixtures/project_b/README.rst
@@ -0,0 +1,3 @@
+
+.. |badge| image:: https://img.shields.io/badge/PyCalVer-v201307.0456--beta-blue.svg
+    :target: https://shields.io/
diff --git a/test/fixtures/project_b/setup.cfg b/test/fixtures/project_b/setup.cfg
index 3f80d12..9eb8230 100644
--- a/test/fixtures/project_b/setup.cfg
+++ b/test/fixtures/project_b/setup.cfg
@@ -10,6 +10,6 @@ setup.cfg =
 setup.py =
     version="{pep440_version}"
 README.rst =
-    img.shields.io/badge/PyCalVer-{calver}{build}--{release}-blue
+    img.shields.io/badge/PyCalVer-{calver}{build}-{release}-blue
 src/module_v*/__init__.py =
     __version__ = "{version}"
diff --git a/test/test_rewrite.py b/test/test_rewrite.py
index 61cad1c..39e1a45 100644
--- a/test/test_rewrite.py
+++ b/test/test_rewrite.py
@@ -1,3 +1,5 @@
+import copy
+
 from pycalver import config
 from pycalver import rewrite
 
@@ -67,3 +69,34 @@ def test_iter_file_globs():
         "src/module_v1/__init__.py",
         "src/module_v2/__init__.py",
     }
+
+
+def test_error_bad_path():
+    with util.Project(project="b") as project:
+        ctx = config.init_project_ctx(project.dir)
+        cfg = config.parse(ctx)
+        assert cfg
+
+        (project.dir / "setup.py").unlink()
+        try:
+            list(rewrite._iter_file_paths(cfg.file_patterns))
+            assert False, "expected ValueError"
+        except ValueError as ex:
+            assert "setup.py" in str(ex)
+
+
+def test_error_bad_pattern():
+    with util.Project(project="b") as project:
+        ctx = config.init_project_ctx(project.dir)
+        cfg = config.parse(ctx)
+        assert cfg
+
+        patterns = copy.deepcopy(cfg.file_patterns)
+        print(patterns)
+        patterns["setup.py"] = patterns["setup.py"][0] + "invalid"
+
+        try:
+            list(rewrite.diff("v201809.1234", patterns))
+            assert False, "expected ValueError"
+        except ValueError as ex:
+            assert "setup.py" in str(ex)