fix(test): check that the needed pdftotext binary is correctly available

test/test_transforms.py

@@ -130,6 +130,15 @@ r2MAoIO1DSsuM23SzgmqubGJEZuSRWhR
                 self.skipTest("pdflatex not installed")
             else:
                 raise
+        try:
+            subprocess.check_call(
+                ["pdftotext", "--help"],
+                cwd=osp.abspath(DATAPATH),
+                stdout=open(os.devnull, "w"),
+            )
+        except OSError as exc:
+            raise Exception(f"pdftotext not installed: {exc}")
+
         data = TransformData(
             open(osp.join(DATAPATH, "hello.pdf"), "rb").read(),
             "application/pdf",