Add pure correction and pedagogy logic with full test coverage

scripts/correction/: AnswerValidator (multiple choice, sentence
correction via tap-the-faulty-word + retype) and DictationAnalyzer
build the CorrectionResult structure from cahier des charges §6.
Dictation analysis aligns words with WordAligner (Wagner-Fischer edit
distance) before any character comparison, so an omitted or added
word doesn't cascade into false errors on every following word.
TextNormalizer handles non-breaking spaces, typographic apostrophes,
and decomposed-vs-composed French accented characters via an
explicit table (GDScript has no built-in NFC/NFD normalization).
Error classification follows the data annotations only (rule_id
present -> grammatical, absent -> unclassified), never a runtime
linguistic guess.

scripts/pedagogy/: DifficultyManager (per-skill difficulty from
recent results), AttemptFlow (3-attempt graduated aid: hint, then
explanation, then reveal, matching exercise-lifecycle.md's second
gap), and ReviewScheduler (the five mastery states from §9, with
session-counted spaced review intervals [1, 3, 6, 12] rather than
wall-clock dates, since a family device's clock isn't trustworthy).

All of it is pure: no scene tree, no clock or RNG read directly,
every effectful input (session number, attempt outcome) is a
parameter. 65 headless tests across both layers, including the
word-omission-doesn't-cascade regression and the full
decouverte -> acquise -> a_reviser -> acquise path.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

tests/correction/test_answer_validator.gd

@@ -0,0 +1,77 @@
+extends GutTest
+## Tests de AnswerValidator (choix multiple et correction de phrase).
+
+var multiple_choice_exercise: Dictionary = {
+    "rule_id": "regle_test",
+    "answers": ["petit", "petits", "petite"],
+    "correct_answer": 1,
+    "hint": "indice",
+    "explanation": "explication",
+}
+
+var sentence_correction_exercise: Dictionary = {
+    "rule_id": "regle_test",
+    "hint": "indice",
+    "explanation": "explication",
+    "tokens":
+    [
+        {"text": "Les", "correct": true},
+        {
+            "text": "petit",
+            "correct": false,
+            "expected": "petits",
+            "rule_id": "regle_accord_adjectif",
+        },
+        {"text": "chiens", "correct": true},
+    ],
+}
+
+
+func test_multiple_choice_correct_answer() -> void:
+    var result := AnswerValidator.validate_multiple_choice(multiple_choice_exercise, 1)
+    assert_true(result.is_correct)
+    assert_eq(result.errors, [])
+
+
+func test_multiple_choice_wrong_answer_reports_found_and_expected() -> void:
+    var result := AnswerValidator.validate_multiple_choice(multiple_choice_exercise, 0)
+    assert_false(result.is_correct)
+    assert_eq(result.errors.size(), 1)
+    assert_eq(result.errors[0]["found"], "petit")
+    assert_eq(result.errors[0]["expected"], "petits")
+    assert_eq(result.errors[0]["rule_id"], "regle_test")
+
+
+func test_sentence_correction_fully_correct() -> void:
+    var result := AnswerValidator.validate_sentence_correction(
+        sentence_correction_exercise, [1], {1: "petits"}
+    )
+    assert_true(result.is_correct)
+
+
+func test_sentence_correction_missed_faulty_token() -> void:
+    var result := AnswerValidator.validate_sentence_correction(sentence_correction_exercise, [], {})
+    assert_false(result.is_correct)
+    assert_eq(result.errors.size(), 1)
+    assert_eq(result.errors[0]["rule_id"], "regle_accord_adjectif")
+    assert_eq(result.errors[0]["found"], "petit")
+    assert_eq(result.errors[0]["expected"], "petits")
+
+
+func test_sentence_correction_wrong_correction_text() -> void:
+    var result := AnswerValidator.validate_sentence_correction(
+        sentence_correction_exercise, [1], {1: "petite"}
+    )
+    assert_false(result.is_correct)
+    assert_eq(result.errors[0]["found"], "petite")
+    assert_eq(result.errors[0]["expected"], "petits")
+
+
+func test_sentence_correction_false_positive_on_correct_token() -> void:
+    var result := AnswerValidator.validate_sentence_correction(
+        sentence_correction_exercise, [1, 2], {1: "petits", 2: "chien"}
+    )
+    assert_false(result.is_correct)
+    assert_eq(result.errors.size(), 1)
+    assert_eq(result.errors[0]["error_type"], "unclassified")
+    assert_eq(result.errors[0]["position"], 2)

tests/correction/test_answer_validator.gd.uid

@@ -0,0 +1 @@
+uid://ctn0svsnq535v

tests/correction/test_dictation_analyzer.gd

@@ -0,0 +1,67 @@
+extends GutTest
+## Tests de DictationAnalyzer : alignement, classification lexicale/grammaticale
+## via annotation, majuscule, variantes acceptees.
+
+var dictation: Dictionary = {
+    "target_text": "Les petits chats dorment.",
+    "words":
+    [
+        {"text": "Les", "expects_capital": true},
+        {"text": "petits", "rule_id": "regle_accord_adjectif"},
+        {"text": "chats"},
+        {"text": "dorment."},
+    ],
+    "accepted_variants": [],
+}
+
+
+func test_exact_match_is_correct() -> void:
+    var result := DictationAnalyzer.analyze(dictation, "Les petits chats dorment.")
+    assert_true(result.is_correct)
+    assert_eq(result.errors, [])
+
+
+func test_annotated_word_error_is_classified_as_grammatical() -> void:
+    var result := DictationAnalyzer.analyze(dictation, "Les petit chats dorment.")
+    assert_false(result.is_correct)
+    assert_eq(result.errors.size(), 1)
+    assert_eq(result.errors[0]["error_type"], "grammatical")
+    assert_eq(result.errors[0]["rule_id"], "regle_accord_adjectif")
+    assert_eq(result.errors[0]["found"], "petit")
+    assert_eq(result.errors[0]["expected"], "petits")
+
+
+func test_unannotated_word_error_is_unclassified() -> void:
+    var result := DictationAnalyzer.analyze(dictation, "Les petits chat dorment.")
+    assert_false(result.is_correct)
+    assert_eq(result.errors.size(), 1)
+    assert_eq(result.errors[0]["error_type"], "unclassified")
+    assert_eq(result.errors[0]["rule_id"], "")
+
+
+func test_missing_word_does_not_cascade_into_further_errors() -> void:
+    # Le mot "petits" est omis : sans alignement, cela provoquerait deux
+    # erreurs en cascade sur "chats" et "dorment.".
+    var result := DictationAnalyzer.analyze(dictation, "Les chats dorment.")
+    assert_false(result.is_correct)
+    assert_eq(result.errors.size(), 1)
+    assert_eq(result.errors[0]["rule_id"], "regle_accord_adjectif")
+
+
+func test_missing_capital_is_reported_separately() -> void:
+    var result := DictationAnalyzer.analyze(dictation, "les petits chats dorment.")
+    assert_false(result.is_correct)
+    assert_eq(result.errors.size(), 1)
+    assert_eq(result.errors[0]["error_type"], "capitalization")
+
+
+func test_accepted_variant_is_treated_as_correct() -> void:
+    var dictation_with_variant: Dictionary = dictation.duplicate(true)
+    dictation_with_variant["accepted_variants"] = ["Les petits chats dorment"]
+    var result := DictationAnalyzer.analyze(dictation_with_variant, "Les petits chats dorment")
+    assert_true(result.is_correct)
+
+
+func test_normalizes_before_comparing() -> void:
+    var result := DictationAnalyzer.analyze(dictation, "Les petits chats dorment.")
+    assert_true(result.is_correct)

tests/correction/test_dictation_analyzer.gd.uid

@@ -0,0 +1 @@
+uid://ta26vku8mxa

tests/correction/test_text_normalizer.gd

@@ -0,0 +1,39 @@
+extends GutTest
+## Tests de TextNormalizer : espaces, apostrophes, caracteres francais decomposes.
+
+
+func test_normalizes_non_breaking_spaces() -> void:
+    var text := "Les petits chats"
+    assert_eq(TextNormalizer.normalize(text), "Les petits chats")
+
+
+func test_normalizes_typographic_apostrophe() -> void:
+    assert_eq(TextNormalizer.normalize("l’école"), "l'école")
+
+
+func test_collapses_multiple_spaces() -> void:
+    assert_eq(TextNormalizer.normalize("Les   petits  chats"), "Les petits chats")
+
+
+func test_recomposes_decomposed_accented_characters() -> void:
+    # "e" + accent aigu combinant (U+0301) doit devenir "é" precompose.
+    var decomposed := "école"
+    assert_eq(TextNormalizer.normalize(decomposed), "école")
+
+
+func test_recomposes_cedille() -> void:
+    var decomposed := "français"
+    assert_eq(TextNormalizer.normalize(decomposed), "français")
+
+
+func test_strips_leading_and_trailing_whitespace() -> void:
+    assert_eq(TextNormalizer.normalize("  bonjour  "), "bonjour")
+
+
+func test_split_words_splits_on_single_spaces() -> void:
+    var words := TextNormalizer.split_words("Les petits chats dorment.")
+    assert_eq(words, ["Les", "petits", "chats", "dorment."])
+
+
+func test_split_words_on_empty_text_returns_empty_array() -> void:
+    assert_eq(TextNormalizer.split_words("   "), [])

tests/correction/test_text_normalizer.gd.uid

@@ -0,0 +1 @@
+uid://dqrgabx44in1k

tests/correction/test_word_aligner.gd

@@ -0,0 +1,45 @@
+extends GutTest
+## Tests de WordAligner : l'alignement doit absorber les mots omis ou ajoutes
+## sans decaler les comparaisons suivantes.
+
+var target: Array[String] = ["Les", "petits", "chats", "dorment."]
+
+
+func test_identical_sequences_are_all_matches() -> void:
+    var ops := WordAligner.align(target, target.duplicate())
+    for op in ops:
+        assert_eq(op["op"], "match")
+    assert_eq(ops.size(), 4)
+
+
+func test_single_substitution_is_detected_at_the_right_position() -> void:
+    var submitted: Array[String] = ["Les", "petit", "chats", "dorment."]
+    var ops := WordAligner.align(target, submitted)
+    assert_eq(ops.size(), 4)
+    assert_eq(ops[1]["op"], "substitute")
+    assert_eq(ops[1]["target_index"], 1)
+    assert_eq(ops[0]["op"], "match")
+    assert_eq(ops[2]["op"], "match")
+    assert_eq(ops[3]["op"], "match")
+
+
+func test_missing_word_is_a_delete_and_does_not_shift_later_matches() -> void:
+    # L'enfant a oublie "petits" : sans alignement, "chats" se comparerait a
+    # "petits" et "dorment." a "chats", generant deux fausses erreurs en cascade.
+    var submitted: Array[String] = ["Les", "chats", "dorment."]
+    var ops := WordAligner.align(target, submitted)
+    assert_eq(ops.size(), 4)
+    assert_eq(ops[0]["op"], "match")
+    assert_eq(ops[1]["op"], "delete")
+    assert_eq(ops[1]["target_index"], 1)
+    assert_eq(ops[2]["op"], "match")
+    assert_eq(ops[2]["target_index"], 2)
+    assert_eq(ops[3]["op"], "match")
+    assert_eq(ops[3]["target_index"], 3)
+
+
+func test_extra_word_is_an_insert() -> void:
+    var submitted: Array[String] = ["Les", "petits", "petits", "chats", "dorment."]
+    var ops := WordAligner.align(target, submitted)
+    var insert_ops: Array = ops.filter(func(op: Dictionary) -> bool: return op["op"] == "insert")
+    assert_eq(insert_ops.size(), 1)

tests/correction/test_word_aligner.gd.uid

@@ -0,0 +1 @@
+uid://de278l35ygq6i

tests/data/test_schema_validator.gd

@@ -6,64 +6,65 @@ var schema: Dictionary = {
     "type": "object",
     "required": ["id", "level"],
     "additionalProperties": false,
-    "properties": {
-        "id": { "type": "string", "pattern": "^[a-z][a-z0-9_]*$" },
-        "level": { "type": "string", "enum": ["CE1", "CE2"] },
-        "difficulty": { "type": "integer", "minimum": 1, "maximum": 3 },
-        "tags": { "type": "array", "minItems": 1, "items": { "type": "string" } },
+    "properties":
+    {
+        "id": {"type": "string", "pattern": "^[a-z][a-z0-9_]*$"},
+        "level": {"type": "string", "enum": ["CE1", "CE2"]},
+        "difficulty": {"type": "integer", "minimum": 1, "maximum": 3},
+        "tags": {"type": "array", "minItems": 1, "items": {"type": "string"}},
     },
 }
 
 
 func test_valid_object_has_no_errors() -> void:
-    var data := { "id": "ex_01", "level": "CE1", "difficulty": 2, "tags": ["pluriel"] }
+    var data := {"id": "ex_01", "level": "CE1", "difficulty": 2, "tags": ["pluriel"]}
     assert_eq(SchemaValidator.validate(data, schema), [])
 
 
 func test_missing_required_property_is_reported() -> void:
-    var data := { "level": "CE1" }
+    var data := {"level": "CE1"}
     var errors := SchemaValidator.validate(data, schema)
     assert_eq(errors.size(), 1)
     assert_string_contains(errors[0], "id")
 
 
 func test_wrong_type_is_reported() -> void:
-    var data := { "id": "ex_01", "level": "CE1", "difficulty": "deux" }
+    var data := {"id": "ex_01", "level": "CE1", "difficulty": "deux"}
     var errors := SchemaValidator.validate(data, schema)
     assert_eq(errors.size(), 1)
     assert_string_contains(errors[0], "difficulty")
 
 
 func test_enum_violation_is_reported() -> void:
-    var data := { "id": "ex_01", "level": "CM1" }
+    var data := {"id": "ex_01", "level": "CM1"}
     var errors := SchemaValidator.validate(data, schema)
     assert_eq(errors.size(), 1)
     assert_string_contains(errors[0], "level")
 
 
 func test_pattern_violation_is_reported() -> void:
-    var data := { "id": "Ex-01", "level": "CE1" }
+    var data := {"id": "Ex-01", "level": "CE1"}
     var errors := SchemaValidator.validate(data, schema)
     assert_eq(errors.size(), 1)
     assert_string_contains(errors[0], "id")
 
 
 func test_unexpected_property_is_reported_when_additional_forbidden() -> void:
-    var data := { "id": "ex_01", "level": "CE1", "extra": true }
+    var data := {"id": "ex_01", "level": "CE1", "extra": true}
     var errors := SchemaValidator.validate(data, schema)
     assert_eq(errors.size(), 1)
     assert_string_contains(errors[0], "extra")
 
 
 func test_min_items_violation_is_reported() -> void:
-    var data := { "id": "ex_01", "level": "CE1", "tags": [] }
+    var data := {"id": "ex_01", "level": "CE1", "tags": []}
     var errors := SchemaValidator.validate(data, schema)
     assert_eq(errors.size(), 1)
     assert_string_contains(errors[0], "tags")
 
 
 func test_numeric_bounds_are_checked() -> void:
-    var data := { "id": "ex_01", "level": "CE1", "difficulty": 9 }
+    var data := {"id": "ex_01", "level": "CE1", "difficulty": 9}
     var errors := SchemaValidator.validate(data, schema)
     assert_eq(errors.size(), 1)
     assert_string_contains(errors[0], "difficulty")

tests/data/test_schema_validator.gd.uid

@@ -0,0 +1 @@
+uid://c3gl78mc1o27p

tests/data/test_semantic_checks.gd

@@ -3,24 +3,24 @@ extends GutTest
 
 
 func test_multiple_choice_rejects_out_of_bounds_correct_answer() -> void:
-    var data := { "answers": ["a", "b"], "correct_answer": 5 }
+    var data := {"answers": ["a", "b"], "correct_answer": 5}
     var errors := SemanticChecks.check_multiple_choice(data, "test")
     assert_eq(errors.size(), 1)
 
 
 func test_multiple_choice_accepts_valid_index() -> void:
-    var data := { "answers": ["a", "b"], "correct_answer": 1 }
+    var data := {"answers": ["a", "b"], "correct_answer": 1}
     assert_eq(SemanticChecks.check_multiple_choice(data, "test"), [])
 
 
 func test_sentence_correction_requires_at_least_one_error_token() -> void:
-    var data := { "tokens": [{ "text": "Les", "correct": true }] }
+    var data := {"tokens": [{"text": "Les", "correct": true}]}
     var errors := SemanticChecks.check_sentence_correction(data, "test")
     assert_eq(errors.size(), 1)
 
 
 func test_sentence_correction_requires_expected_on_error_tokens() -> void:
-    var data := { "tokens": [{ "text": "petit", "correct": false }] }
+    var data := {"tokens": [{"text": "petit", "correct": false}]}
     var errors := SemanticChecks.check_sentence_correction(data, "test")
     assert_eq(errors.size(), 1)
     assert_string_contains(errors[0], "expected")
@@ -29,7 +29,7 @@ func test_sentence_correction_requires_expected_on_error_tokens() -> void:
 func test_dictation_word_count_must_match_target_text() -> void:
     var data := {
         "target_text": "Les petits chats dorment.",
-        "words": [{ "text": "Les" }, { "text": "petits" }],
+        "words": [{"text": "Les"}, {"text": "petits"}],
     }
     var errors := SemanticChecks.check_dictation(data, "test")
     assert_eq(errors.size(), 1)
@@ -38,8 +38,6 @@ func test_dictation_word_count_must_match_target_text() -> void:
 func test_dictation_accepts_matching_word_count() -> void:
     var data := {
         "target_text": "Les petits chats dorment.",
-        "words": [
-            { "text": "Les" }, { "text": "petits" }, { "text": "chats" }, { "text": "dorment." }
-        ],
+        "words": [{"text": "Les"}, {"text": "petits"}, {"text": "chats"}, {"text": "dorment."}],
     }
     assert_eq(SemanticChecks.check_dictation(data, "test"), [])

tests/data/test_semantic_checks.gd.uid

@@ -0,0 +1 @@
+uid://bxlm60qsghevm

tests/pedagogy/test_attempt_flow.gd

@@ -0,0 +1,19 @@
+extends GutTest
+## Tests de AttemptFlow : aide graduee sur 3 tentatives, sortie sans blocage.
+
+
+func test_first_error_gives_a_hint() -> void:
+    assert_eq(AttemptFlow.support_level_for_attempt(1), AttemptFlow.SupportLevel.HINT)
+
+
+func test_second_error_gives_an_explanation() -> void:
+    assert_eq(AttemptFlow.support_level_for_attempt(2), AttemptFlow.SupportLevel.EXPLANATION)
+
+
+func test_third_error_reveals_the_answer() -> void:
+    assert_eq(AttemptFlow.support_level_for_attempt(3), AttemptFlow.SupportLevel.REVEAL)
+
+
+func test_exercise_ends_at_max_attempts() -> void:
+    assert_false(AttemptFlow.should_end_exercise(2))
+    assert_true(AttemptFlow.should_end_exercise(3))

tests/pedagogy/test_attempt_flow.gd.uid

@@ -0,0 +1 @@
+uid://dkijvppw88nt8

tests/pedagogy/test_difficulty_manager.gd

@@ -0,0 +1,32 @@
+extends GutTest
+## Tests de DifficultyManager.
+
+
+func test_three_consecutive_successes_raise_difficulty() -> void:
+    var recent: Array[bool] = [true, true, true]
+    assert_eq(DifficultyManager.next_difficulty(1, recent), 2)
+
+
+func test_three_consecutive_failures_lower_difficulty() -> void:
+    var recent: Array[bool] = [false, false, false]
+    assert_eq(DifficultyManager.next_difficulty(2, recent), 1)
+
+
+func test_mixed_results_keep_difficulty_stable() -> void:
+    var recent: Array[bool] = [true, false, true]
+    assert_eq(DifficultyManager.next_difficulty(2, recent), 2)
+
+
+func test_difficulty_never_exceeds_maximum() -> void:
+    var recent: Array[bool] = [true, true, true]
+    assert_eq(DifficultyManager.next_difficulty(3, recent), 3)
+
+
+func test_difficulty_never_goes_below_minimum() -> void:
+    var recent: Array[bool] = [false, false, false]
+    assert_eq(DifficultyManager.next_difficulty(1, recent), 1)
+
+
+func test_not_enough_history_keeps_difficulty_unchanged() -> void:
+    var recent: Array[bool] = [true, true]
+    assert_eq(DifficultyManager.next_difficulty(2, recent), 2)

tests/pedagogy/test_difficulty_manager.gd.uid

@@ -0,0 +1 @@
+uid://tglbwa62prwa

tests/pedagogy/test_review_scheduler.gd

@@ -0,0 +1,133 @@
+extends GutTest
+## Tests de ReviewScheduler : transitions de maitrise (cahier des charges §9)
+## et planification des revisions en seances (pas en dates calendaires).
+
+
+func _attempt(
+    success: bool, hint_used: bool = false, exercise_type: String = "multiple_choice"
+) -> Dictionary:
+    return {"success": success, "hint_used": hint_used, "exercise_type": exercise_type}
+
+
+func test_initial_state_is_decouverte() -> void:
+    assert_eq(ReviewScheduler.initial_state()["status"], ReviewScheduler.STATUS_DECOUVERTE)
+
+
+func test_first_success_moves_to_en_acquisition() -> void:
+    var state := ReviewScheduler.record_attempt(ReviewScheduler.initial_state(), _attempt(true), 1)
+    assert_eq(state["status"], ReviewScheduler.STATUS_EN_ACQUISITION)
+
+
+func test_first_failure_stays_at_decouverte() -> void:
+    var state := ReviewScheduler.record_attempt(ReviewScheduler.initial_state(), _attempt(false), 1)
+    assert_eq(state["status"], ReviewScheduler.STATUS_DECOUVERTE)
+
+
+func test_two_hintless_successes_reach_en_consolidation() -> void:
+    var state := ReviewScheduler.initial_state()
+    state = ReviewScheduler.record_attempt(state, _attempt(true), 1)
+    state = ReviewScheduler.record_attempt(state, _attempt(true), 1)
+    assert_eq(state["status"], ReviewScheduler.STATUS_EN_CONSOLIDATION)
+
+
+func test_successes_with_hints_do_not_reach_en_consolidation() -> void:
+    var state := ReviewScheduler.initial_state()
+    state = ReviewScheduler.record_attempt(state, _attempt(true, true), 1)
+    state = ReviewScheduler.record_attempt(state, _attempt(true, true), 1)
+    assert_eq(state["status"], ReviewScheduler.STATUS_EN_ACQUISITION)
+
+
+func test_full_path_to_acquise_requires_sessions_and_formats() -> void:
+    var state := ReviewScheduler.initial_state()
+    var sessions := [1, 1, 2, 2, 3, 3, 4, 4]
+    var types := ["multiple_choice", "sentence_correction"]
+    for i in 8:
+        state = ReviewScheduler.record_attempt(
+            state, _attempt(true, false, types[i % 2]), sessions[i]
+        )
+    assert_eq(state["status"], ReviewScheduler.STATUS_ACQUISE)
+    assert_eq(state["review_interval_index"], 0)
+    assert_eq(state["next_review_session"], 4 + ReviewScheduler.REVIEW_INTERVALS_SESSIONS[0])
+
+
+func test_acquise_requires_at_least_three_distinct_sessions() -> void:
+    var state := ReviewScheduler.initial_state()
+    var types := ["multiple_choice", "sentence_correction"]
+    # 8 succes mais seulement 2 seances distinctes : ne doit pas atteindre "acquise".
+    for i in 8:
+        state = ReviewScheduler.record_attempt(
+            state, _attempt(true, false, types[i % 2]), 1 if i < 4 else 2
+        )
+    assert_ne(state["status"], ReviewScheduler.STATUS_ACQUISE)
+
+
+func test_acquise_requires_at_least_two_distinct_formats() -> void:
+    var state := ReviewScheduler.initial_state()
+    var sessions := [1, 1, 2, 2, 3, 3, 4, 4]
+    for i in 8:
+        state = ReviewScheduler.record_attempt(state, _attempt(true), sessions[i])
+    assert_ne(state["status"], ReviewScheduler.STATUS_ACQUISE)
+
+
+func _make_acquise_state(interval_index: int, next_review_session: int) -> Dictionary:
+    var state := ReviewScheduler.initial_state()
+    state["status"] = ReviewScheduler.STATUS_ACQUISE
+    state["recent_results"] = [true, true, true, true, true, true, true, true]
+    state["recent_hint_used"] = [false, false, false, false, false, false, false, false]
+    state["sessions_succeeded"] = [1, 2, 3]
+    state["formats_succeeded"] = ["multiple_choice", "sentence_correction"]
+    state["review_interval_index"] = interval_index
+    state["next_review_session"] = next_review_session
+    return state
+
+
+func test_failure_on_acquise_skill_moves_to_a_reviser() -> void:
+    var state := _make_acquise_state(0, 99)
+    state = ReviewScheduler.record_attempt(state, _attempt(false), 5)
+    assert_eq(state["status"], ReviewScheduler.STATUS_A_REVISER)
+    assert_eq(state["next_review_session"], -1)
+
+
+func test_success_on_a_reviser_skill_returns_to_acquise_at_first_interval() -> void:
+    var state := _make_acquise_state(2, 99)
+    state["status"] = ReviewScheduler.STATUS_A_REVISER
+    state = ReviewScheduler.record_attempt(state, _attempt(true), 10)
+    assert_eq(state["status"], ReviewScheduler.STATUS_ACQUISE)
+    assert_eq(state["review_interval_index"], 0)
+    assert_eq(state["next_review_session"], 10 + ReviewScheduler.REVIEW_INTERVALS_SESSIONS[0])
+
+
+func test_successful_review_on_time_advances_to_next_interval() -> void:
+    var state := _make_acquise_state(0, 5)
+    assert_true(ReviewScheduler.is_due_for_review(state, 5))
+    state = ReviewScheduler.record_attempt(state, _attempt(true), 5)
+    assert_eq(state["status"], ReviewScheduler.STATUS_ACQUISE)
+    assert_eq(state["review_interval_index"], 1)
+    assert_eq(state["next_review_session"], 5 + ReviewScheduler.REVIEW_INTERVALS_SESSIONS[1])
+
+
+func test_success_before_due_date_does_not_advance_interval() -> void:
+    var state := _make_acquise_state(0, 10)
+    assert_false(ReviewScheduler.is_due_for_review(state, 5))
+    state = ReviewScheduler.record_attempt(state, _attempt(true), 5)
+    assert_eq(state["review_interval_index"], 0)
+    assert_eq(state["next_review_session"], 10)
+
+
+func test_review_interval_never_exceeds_last_step() -> void:
+    var last_index := ReviewScheduler.REVIEW_INTERVALS_SESSIONS.size() - 1
+    var state := _make_acquise_state(last_index, 5)
+    state = ReviewScheduler.record_attempt(state, _attempt(true), 5)
+    assert_eq(state["review_interval_index"], last_index)
+
+
+func test_mark_overdue_as_review_transitions_without_new_attempt() -> void:
+    var state := _make_acquise_state(0, 5)
+    var updated := ReviewScheduler.mark_overdue_as_review(state, 6)
+    assert_eq(updated["status"], ReviewScheduler.STATUS_A_REVISER)
+
+
+func test_mark_overdue_as_review_does_nothing_before_due_date() -> void:
+    var state := _make_acquise_state(0, 5)
+    var updated := ReviewScheduler.mark_overdue_as_review(state, 3)
+    assert_eq(updated["status"], ReviewScheduler.STATUS_ACQUISE)

tests/pedagogy/test_review_scheduler.gd.uid

@@ -0,0 +1 @@
+uid://cryfvtynu2fue