Learn
One unit at a time by default. Reach Level 2+ on every card in a unit before the next unlocks. Prompts step from multiple choice → typing → flashcard.
Up to 10 cards per round. Practice any cards ignores the due schedule.
Quiz
Shuffled multiple-choice from the guide. Calculation questions use new numbers each time. You can retry missed questions at the end.
Labs
Hands-on demos from the guide. Everything starts at zero / empty — change inputs and watch the result update. Not scored.
Pairwise coverage
- Factors are binary A, B, C. Each button is one test row (e.g.
101means A=1, B=0, C=1). - Tap rows to include or remove them. The right panel counts how many of the 12 required pair values (AB/AC/BC × 00/01/10/11) you covered.
- Goal: cover all 12 pairwise items. Try it with only four rows. Pair coverage is not the same as covering all 8 full triples.
Study guide · pages 13–15
Boundary values
- Enter an exam score (valid integers 0–75) and coursework (valid integers 0–25), then press Check grade.
- Valid totals: D 0–29, C 30–49, B 50–69, A 70–100. Anything outside the input ranges is FM.
- Use the preset buttons to jump to boundaries (e.g. 29 vs 30) or invalid inputs. Trap: 15+15 = 30 → C, even if a slide table says FM.
Boundary / invalid presets:
Trap: 15 + 15 is a valid total of 30 → grade C. Some slides mark that cell FM; follow the stated rule, not the inconsistent table.
Study guide · page 9
Data-flow paths
- The program has two decisions: I (x > 10) and II (y > 10). A path like TF means I true, II false.
- Tap path buttons to include tests. The right panel shows branch outcomes (4) and definition–use pairs (12).
- Start empty. Try TT + FF first (full branch coverage), then add TF/FT and watch remaining DU pairs fill in.
1 input x, y; a = 0; b = 0
I if x > 10:
2 w = a + 1; b = 4
else:
3 w = b + 1; a = 4
II if y > 10:
4 z = a + w
else:
5 z = b + wStudy guide · pages 22–23 · 12 definition–use pairs
Symbolic paths
- Enter starting x and y (defaults 0), then press Trace.
- Press Next step to walk through decisions P then Q and see values update.
- Use the example buttons for known feasible paths. FT is impossible — open the note below for why.
P: if x ≤ 0 or y ≤ 0:
x = x²; y = y²
else:
x = x + 1; y = y + 1
Q: if x < 1 or y < 1:
x = x + 1; y = y + 1
else:
x = x - 1; y = y - 1Known feasible examples:
Why is FT impossible?
P=false requires x>0 and y>0. Incrementing both makes each updated value greater than 1. Therefore Q (x<1 or y<1) must be false.
Writing algebra for a path does not prove the path is feasible. Its constraints must also be satisfiable.
Study guide · page 26
Reference
Formulas, lookalike pairs, and glossary. Not a study round.
Formulas & scoring
Watch denominator traps on coverage and mutation score.
Verification vs validation
- Verification
- Built the product right — conformance to a specification.
- Validation
- Built the right product — fitness for user needs.
Retest vs regression
- Retesting
- Checks that a specific defect was fixed.
- Regression
- Checks that a change did not break previously working behavior.
Statement vs branch
- Statement coverage
- Execute statements. Need not hit every branch.
- Branch coverage
- Exercise each decision outcome.
Condition vs decision
- Condition coverage
- Each atomic condition true and false.
- Decision coverage
- Each overall decision outcome. Neither implies the other.
Items vs suite size
- Pairwise items
- How many value-pairs must appear (e.g. 12 for 3 binary factors).
- Suite size
- How many test rows you run. Different denominator.
Error → defect → failure
- Error
- Human mistake.
- Defect
- Fault in an artifact. May not fail on every run.
- Failure
- Observable incorrect behavior.