From 2c49e06678974653f92fef045dc678068b53b9b9 Mon Sep 17 00:00:00 2001
From: Theofilos Manitaras <manitaras@cscs.ch>
Date: Thu, 26 Nov 2020 17:52:10 +0100
Subject: [PATCH 1/3] Add Github action to check for unused imports

---
 .github/workflows/main.yml | 22 ++++++++++++++++++++++
 reframe/frontend/cli.py    |  1 -
 reframe/frontend/loader.py |  3 +--
 3 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index c267ccf0bb..51ecacb250 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -46,3 +46,25 @@ jobs:
     - name: Run Unittests
       run: |
         docker run reframe:${{ matrix.modules-version }}
+
+  flake8:
+    if: github.event_name == 'pull_request'
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+      with:
+        fetch-depth: 0
+    - name: Changed Python Files
+      run: |
+        echo 'CHANGED_PYTHON_FILES<<EOF' >> $GITHUB_ENV
+        git diff --name-only ${{ github.event.pull_request.base.sha }}..${{ github.sha }} | grep '.py' >> $GITHUB_ENV
+        echo 'EOF' >> $GITHUB_ENV
+    - uses: actions/setup-python@v2
+      with:
+        python-version: 3.8
+    - name: Unused Imports Check
+      run: |
+        pip install flake8
+        echo 'Checking Python Files:'
+        for f in "$CHANGED_PYTHON_FILES"; do echo "$f"; done
+        flake8 --select F401 $CHANGED_PYTHON_FILES
diff --git a/reframe/frontend/cli.py b/reframe/frontend/cli.py
index 984c7c3f8a..1c3e962536 100644
--- a/reframe/frontend/cli.py
+++ b/reframe/frontend/cli.py
@@ -16,7 +16,6 @@
 
 import reframe
 import reframe.core.config as config
-import reframe.core.environments as env
 import reframe.core.exceptions as errors
 import reframe.core.logging as logging
 import reframe.core.runtime as runtime
diff --git a/reframe/frontend/loader.py b/reframe/frontend/loader.py
index e1f1b56b2f..299a365e6d 100644
--- a/reframe/frontend/loader.py
+++ b/reframe/frontend/loader.py
@@ -10,12 +10,11 @@
 import ast
 import collections.abc
 import inspect
-import io
 import os
 
 import reframe.utility as util
 import reframe.utility.osext as osext
-from reframe.core.exceptions import NameConflictError, RegressionTestLoadError
+from reframe.core.exceptions import NameConflictError
 from reframe.core.logging import getlogger
 
 

From a2507ee68602ec117e8c859e223209c8607eff52 Mon Sep 17 00:00:00 2001
From: Theofilos Manitaras <manitaras@cscs.ch>
Date: Thu, 26 Nov 2020 18:18:51 +0100
Subject: [PATCH 2/3] Dummy change to test unused import

---
 reframe/frontend/cli.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/reframe/frontend/cli.py b/reframe/frontend/cli.py
index 1c3e962536..0dced783a7 100644
--- a/reframe/frontend/cli.py
+++ b/reframe/frontend/cli.py
@@ -7,6 +7,7 @@
 import itertools
 import json
 import os
+import math
 import re
 import shlex
 import socket

From ff17404dcd1f5ef817022d52ff21e4232f13fadf Mon Sep 17 00:00:00 2001
From: Vasileios Karakasis <karakasis@cscs.ch>
Date: Sat, 28 Nov 2020 14:36:53 +0100
Subject: [PATCH 3/3] Revert "Dummy change to test unused import"

This reverts commit a2507ee68602ec117e8c859e223209c8607eff52.
---
 reframe/frontend/cli.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/reframe/frontend/cli.py b/reframe/frontend/cli.py
index 0dced783a7..1c3e962536 100644
--- a/reframe/frontend/cli.py
+++ b/reframe/frontend/cli.py
@@ -7,7 +7,6 @@
 import itertools
 import json
 import os
-import math
 import re
 import shlex
 import socket