IDENTIFICATION DIVISION.
       PROGRAM-ID. MinimalPgmEdge.
      *> ============================================================
      *> 最小限プログラム境界テスト (Minimal Program Edge Cases)
      *> 型判定下限: どのタイプにも分類できない極小プログラム
      *>
      *> T1: PROCEDURE DIVISIONだけで何もしない
      *> T2: STOP RUNのみ
      *> T3: DISPLAYのみ
      *> T4: CALL+Gobackのみ (Subprogram最小)
      *> T5: IFのみでELSEなし
      *> T6: 空PERFORM
      *> T7: 88-levelのみ判定 (ファイル入出力なし)
      *> T8: 全ての分岐を省略 (fall-through only)
      *> ============================================================

       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01 WS-PASS          PIC 9(2) VALUE 0.
       01 WS-FAIL          PIC 9(2) VALUE 0.
       01 WS-X             PIC 9(1) VALUE 0.
       01 WS-Y             PIC 9(1) VALUE 1.

       PROCEDURE DIVISION.
       MAIN.
           DISPLAY "MINIMAL-EDGE: Minimal program edge tests"

      *> T1: 空PERFORM
           ADD 1 TO WS-PASS.
           PERFORM EMPTY-PARA.
           DISPLAY "T1-EMPTY-PERFORM: PASS".

      *> T2: IFのみELSEなし
           ADD 1 TO WS-PASS.
           IF WS-X = 0
               DISPLAY "T2-IF-ONLY: x=0 true (no ELSE) PASS"
           END-IF.

      *> T3: IF FALSE (何もしない)
           ADD 1 TO WS-PASS.
           IF WS-X = 1
               DISPLAY "T3-IF-FALSE: SHOULD NOT REACH"
               ADD 1 TO WS-FAIL
           END-IF.
           DISPLAY "T3-IF-FALSE: skipped correctly PASS".

      *> T4: 88-levelのみ (ファイルなし)
           ADD 1 TO WS-PASS.
           IF WS-PASS > WS-FAIL
               DISPLAY "T4-88-ONLY: relational op PASS"
           END-IF.

      *> T5: PERFORM VARYING 0回
           ADD 1 TO WS-PASS.
           PERFORM VARYING WS-X FROM 1 BY 1 UNTIL WS-X > 0
               DISPLAY "T5-ZERO-ITER: EXPECTED NOT REACH"
               ADD 1 TO WS-FAIL
           END-PERFORM.
           DISPLAY "T5-ZERO-ITER: 0 iterations PASS".

      *> T6: 段落スルー (FROM paragraph)
           ADD 1 TO WS-PASS.
           GO TO T6-PARA.
       T6-END.
           DISPLAY "T6-FALL-THRU: reached PASS".
           GO TO T6-DONE.
       T6-PARA.
           DISPLAY "  T6-PARA: entering"
           GO TO T6-END.
       T6-DONE.
           CONTINUE.

           DISPLAY " "
           DISPLAY "MINIMAL-EDGE: PASS=" WS-PASS " FAIL=" WS-FAIL
           IF WS-FAIL = 0
               DISPLAY "ALL PASSED"
               STOP RUN RETURNING 0
           ELSE
               STOP RUN RETURNING 1
           END-IF
           .

       EMPTY-PARA.
           EXIT.
           .

       END PROGRAM MinimalPgmEdge.