[mix-messy-graph] Implement verification

Author: woojiahao

mix_messy_graph/verify.py

@@ -3,9 +3,94 @@
     GitAutograderExercise,
     GitAutograderStatus,
 )
+from itertools import zip_longest
+
+SQUASH_NOT_USED = (
+    "You should be using squash merges for both 'feature-search' and 'feature-delete'"
+)
+WRONG_ORDER_OF_MERGING = "You need to merge 'feature-search' before 'feature-delete'"
+FEATURE_SEARCH_MERGE_MESSAGE = (
+    "The message for merging 'feature-search' should be 'Add the search feature'"
+)
+FEATURE_DELETE_MERGE_MESSAGE = (
+    "The message for merging 'feature-delete' should be 'Add the delete feature'"
+)
+MISMATCH_COMMIT_MESSAGE = (
+    "Expected commit message of '{expected}', got '{given}' instead."
+)
+
+FEATURE_SEARCH_BRANCH_STILL_EXISTS = "Branch 'feature-search' still exists."
+FEATURE_DELETE_BRANCH_STILL_EXISTS = "Branch 'feature-delete' still exists."
+LIST_BRANCH_STILL_EXISTS = "Branch 'list' still exists."
+
+MISSING_FEATURES_FILE = "You are missing 'features.md'!"
+FEATURES_FILE_CONTENT_INVALID = "Contents of 'features.md' is not valid! Try again!"
+
+EXPECTED_COMMIT_MESSAGES = [
+    "Add features.md",
+    "Mention feature for creating books",
+    "Fix phrasing of heading",
+    "Add the search feature",
+    "Add the delete feature",
+]
+
+EXPECTED_LINES = [
+    "# Features",
+    "## Create Book",
+    "Allows creating one book at a time.",
+    "## Searching for Books",
+    "Allows searching for books by keywords.",
+    "Works only for book titles.",
+    "## Deleting Books",
+    "Allows deleting books.",
+]
+
+
+def ensure_str(val) -> str:
+    if isinstance(val, bytes):
+        return val.decode("utf-8", errors="replace").strip()
+    return str(val).strip()
 
 
 def verify(exercise: GitAutograderExercise) -> GitAutograderOutput:
-    # INSERT YOUR GRADING CODE HERE
+    main_branch = exercise.repo.branches.branch("main")
+    merge_commits = [c for c in main_branch.commits if len(c.parents) > 1]
+    if len(merge_commits) > 0:
+        raise exercise.wrong_answer([SQUASH_NOT_USED])
+
+    commit_messages = [ensure_str(c.commit.message) for c in main_branch.commits][::-1]
+    for expected, given in zip_longest(EXPECTED_COMMIT_MESSAGES, commit_messages):
+        if expected != given:
+            raise exercise.wrong_answer(
+                [
+                    MISMATCH_COMMIT_MESSAGE.format(
+                        expected=expected, given=(given or "<Missing commit>")
+                    )
+                ]
+            )
+
+    feature_search_branch = exercise.repo.branches.branch_or_none("feature-search")
+    feature_delete_branch = exercise.repo.branches.branch_or_none("feature-delete")
+    list_branch = exercise.repo.branches.branch_or_none("list")
+    branch_exists_messages = []
+    if feature_search_branch is not None:
+        branch_exists_messages.append(FEATURE_SEARCH_BRANCH_STILL_EXISTS)
+    if feature_delete_branch is not None:
+        branch_exists_messages.append(FEATURE_DELETE_BRANCH_STILL_EXISTS)
+    if list_branch is not None:
+        branch_exists_messages.append(LIST_BRANCH_STILL_EXISTS)
+
+    if branch_exists_messages:
+        raise exercise.wrong_answer(branch_exists_messages)
+
+    with exercise.repo.files.file_or_none("features.md") as features_file:
+        if features_file is None:
+            raise exercise.wrong_answer([MISSING_FEATURES_FILE])
+
+        contents = [
+            line.strip() for line in features_file.readlines() if line.strip() != ""
+        ]
+        if contents != EXPECTED_LINES:
+            raise exercise.wrong_answer([FEATURES_FILE_CONTENT_INVALID])
 
     return exercise.to_output([], GitAutograderStatus.SUCCESSFUL)