| Testing items | Safety-critical system | General system | Lower system | ||||||
| KIa | IIb | UIc | KI | II | UI | II | UI | ||
| Code review | Desk check, etc. | ○d | ○ | ○ | ○ | ○ | ○ | ○ | Δe |
| Data testing | Process boundary | ○ | ○ | ○ | ○ | ○ | Δ | ○ | f |
| Format & interface | ○ | ○ | ○ | ○ | ○ | Δ | Δ | Δ | |
| Safety | ○ | ○ | ○ | ○ | ○ | ○ | ○ | Δ | |
| Functin and state testing | 0-switch requirement | ○ | ○ | ○ | ○ | ○ | Δ | Δ |
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| N-switch requirement | ○ | Δ | Δ | Δ |
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