Implement exercise T6L2/ff-undo

ff_undo/.gitmastery-exercise.json

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+{
+  "exercise_name": "ff-undo",
+  "tags": [
+    "git-branch",
+    "git-merge",
+    "git-reset"
+  ],
+  "requires_git": true,
+  "requires_github": false,
+  "base_files": {},
+  "exercise_repo": {
+    "repo_type": "local",
+    "repo_name": "play-characters",
+    "repo_title": null,
+    "create_fork": null,
+    "init": true
+  }
+}

ff_undo/README.md

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+See https://git-mastery.github.io/lessons/merge/exercise-ff-undo.html

ff_undo/download.py

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+from exercise_utils.git import (
+    add,
+    commit,
+    checkout,
+    merge,
+)
+from exercise_utils.file import (
+    create_or_update_file,
+    append_to_file,
+)
+
+
+def setup(verbose: bool = False):
+    create_or_update_file(
+        "rick.txt",
+        """
+        Hero
+        """,
+    )
+    add(["."], verbose)
+    commit("Add Rick", verbose)
+
+    create_or_update_file(
+        "morty.txt",
+        """
+        Boy
+        """,
+    )
+    add(["."], verbose)
+    commit("Add Morty", verbose)
+
+    checkout("others", True, verbose)
+
+    create_or_update_file(
+        "birdperson.txt",
+        """
+        No job
+        """,
+    )
+    add(["."], verbose)
+    commit("Add Birdperson", verbose)
+
+    append_to_file(
+        "birdperson.txt",
+        """
+        Cyborg
+        """,
+    )
+    add(["."], verbose)
+    commit("Add Cyborg to birdperson.txt", verbose)
+
+    create_or_update_file(
+        "tammy.txt",
+        """
+        Spy
+        """,
+    )
+    add(["."], verbose)
+    commit("Add Tammy", verbose)
+
+    checkout("main", False, verbose)
+    merge("others", True, verbose)

ff_undo/tests/specs/base.yml

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+initialization:
+  steps:
+    - type: commit
+      empty: true
+      message: Set initial state
+      id: start
+    - type: commit
+      message: "Add Rick"
+    - type: commit
+      message: "Add Morty"
+    - type: branch
+      branch-name: others
+    - type: checkout
+      branch-name: others
+    - type: commit
+      message: "Add Birdperson"
+    - type: commit
+      message: "Add Cyborg to birdperson.txt"
+    - type: commit
+      message: "Add Tammy"
+    - type: checkout
+      branch-name: main

ff_undo/tests/specs/branch_missing.yml

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+initialization:
+  steps:
+    - type: commit
+      empty: true
+      message: Set initial state
+      id: start
+    - type: commit
+      message: "Add Rick"
+    - type: commit
+      message: "Add Morty"

ff_undo/tests/specs/main_commits_incorrect.yml

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+initialization:
+  steps:
+    - type: commit
+      empty: true
+      message: Set initial state
+      id: start
+    - type: commit
+      message: "Add Morty"
+    - type: branch
+      branch-name: others
+    - type: checkout
+      branch-name: others
+    - type: commit
+      message: "Add Birdperson"
+    - type: commit
+      message: "Add Cyborg to birdperson.txt"
+    - type: commit
+      message: "Add Tammy"

ff_undo/tests/specs/merge_not_undone.yml

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+initialization:
+  steps:
+    - type: commit
+      empty: true
+      message: Set initial state
+      id: start
+    - type: commit
+      message: "Add Rick"
+    - type: commit
+      message: "Add Morty"
+    - type: branch
+      branch-name: others
+    - type: checkout
+      branch-name: others
+    - type: commit
+      message: "Add Birdperson"
+    - type: commit
+      message: "Add Cyborg to birdperson.txt"
+    - type: commit
+      message: "Add Tammy"
+    - type: checkout
+      branch-name: main
+    - type: merge
+      branch-name: others
+      no-ff: false
+      message: "Introduce others"

ff_undo/tests/specs/others_commits_incorrect.yml

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+initialization:
+  steps:
+    - type: commit
+      empty: true
+      message: Set initial state
+      id: start
+    - type: commit
+      message: "Add Rick"
+    - type: commit
+      message: "Add Morty"
+    - type: branch
+      branch-name: others
+    - type: checkout
+      branch-name: others
+    - type: commit
+      message: "Add Birdperson"
+    - type: commit
+      message: "Add Tammy"

ff_undo/tests/test_verify.py

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+from git_autograder import GitAutograderTestLoader, assert_output
+from git_autograder.status import GitAutograderStatus
+from ..verify import (
+    MERGE_NOT_UNDONE,
+    MAIN_COMMITS_INCORRECT,
+    OTHERS_COMMITS_INCORRECT,
+    OTHERS_BRANCH_MISSING,
+    verify,
+)
+
+REPOSITORY_NAME = "ff-undo"
+
+loader = GitAutograderTestLoader(__file__, REPOSITORY_NAME, verify)
+
+
+def test_correct_solution():
+    with loader.load("specs/base.yml") as output:
+        assert_output(output, GitAutograderStatus.SUCCESSFUL)
+
+
+def test_merge_not_undone():
+    with loader.load("specs/merge_not_undone.yml") as output:
+        assert_output(output, GitAutograderStatus.UNSUCCESSFUL, [MERGE_NOT_UNDONE])
+
+
+def test_branch_missing():
+    with loader.load("specs/branch_missing.yml") as output:
+        assert_output(output, GitAutograderStatus.UNSUCCESSFUL, [OTHERS_BRANCH_MISSING])
+
+
+def test_main_commits_incorrect():
+    with loader.load("specs/main_commits_incorrect.yml") as output:
+        assert_output(
+            output, GitAutograderStatus.UNSUCCESSFUL, [MAIN_COMMITS_INCORRECT]
+        )
+
+
+def test_others_commits_incorrect():
+    with loader.load("specs/others_commits_incorrect.yml") as output:
+        assert_output(
+            output, GitAutograderStatus.UNSUCCESSFUL, [OTHERS_COMMITS_INCORRECT]
+        )

ff_undo/verify.py

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+from git_autograder import (
+    GitAutograderOutput,
+    GitAutograderExercise,
+    GitAutograderStatus,
+)
+
+ADD_RICK = "Add Rick"
+ADD_MORTY = "Add Morty"
+ADD_BIRDPERSON = "Add Birdperson"
+ADD_CYBORG = "Add Cyborg to birdperson.txt"
+ADD_TAMMY = "Add Tammy"
+
+MERGE_NOT_UNDONE = "The merge has not been undone properly."
+MAIN_COMMITS_INCORRECT = "The main branch does not contain the expected commits."
+OTHERS_COMMITS_INCORRECT = "The others branch does not contain the expected commits."
+OTHERS_BRANCH_MISSING = "Missing branch 'others'."
+
+
+def verify(exercise: GitAutograderExercise) -> GitAutograderOutput:
+    main_branch = exercise.repo.branches.branch("main")
+    others_branch = exercise.repo.branches.branch_or_none("others")
+
+    if others_branch is None:
+        raise exercise.wrong_answer([OTHERS_BRANCH_MISSING])
+
+    # Verify commits in main branch
+    commit_messages_in_main = [c.commit.message.strip() for c in main_branch.commits]
+    if any(
+        msg in commit_messages_in_main
+        for msg in [ADD_BIRDPERSON, ADD_CYBORG, ADD_TAMMY]
+    ):
+        raise exercise.wrong_answer([MERGE_NOT_UNDONE])
+
+    if len(commit_messages_in_main) != 3 or not all(
+        msg in commit_messages_in_main for msg in [ADD_RICK, ADD_MORTY]
+    ):
+        raise exercise.wrong_answer([MAIN_COMMITS_INCORRECT])
+
+    # Verify commits in others branch
+    commit_messages_in_others = [
+        c.commit.message.strip() for c in others_branch.commits
+    ]
+    if len(commit_messages_in_others) != 6 or not all(
+        msg in commit_messages_in_others
+        for msg in [ADD_BIRDPERSON, ADD_CYBORG, ADD_TAMMY, ADD_RICK, ADD_MORTY]
+    ):
+        raise exercise.wrong_answer([OTHERS_COMMITS_INCORRECT])
+
+    return exercise.to_output(
+        ["You have successfully undone the merge of branch 'others'."],
+        GitAutograderStatus.SUCCESSFUL,
+    )