[Tests] makes sure --version works

Directly reads the version number from pyproject.toml

features/regression.feature

@@ -122,3 +122,9 @@ Feature: Zapped bugs should stay dead.
         Then the output should contain "This thing happened yesterday"
         Then the output should contain "Adding an entry right now."
         Then the output should not contain "A future entry."
+
+    Scenario: Version numbers should stay in sync
+        Given we use the config "basic.yaml"
+        When we run "jrnl --version"
+        Then we should get no error
+        Then the output should contain pyproject.toml version

features/steps/core.py

@@ -19,6 +19,8 @@ import keyring
 import tzlocal
 import shlex
 import sys
+from pathlib import Path
+import tomlkit
 
 consts = pdt.Constants(usePyICU=False)
 consts.DOWParseStyle = -1  # Prefers past weekdays
@@ -207,6 +209,15 @@ def check_output_time_inline(context, text):
     assert output_date in out, output_date
 
 
+@then('the output should contain pyproject.toml version')
+def check_output_version_inline(context):
+    out = context.stdout_capture.getvalue()
+    pyproject = (Path(__file__) / '..'  / '..'  / '..' / 'pyproject.toml').resolve()
+    pyproject_contents = tomlkit.parse(pyproject.open().read())
+    pyproject_version = pyproject_contents['tool']['poetry']['version']
+    assert pyproject_version in out, pyproject_version
+
+
 @then("the output should contain")
 @then('the output should contain "{text}"')
 @then('the output should contain "{text}" or "{text2}"')