[
 {
  "name": "a mark exactly on the top boundary earns the top grade",
  "args": [
   78,
   100,
   [
    {
     "grade": "9",
     "minMark": 78
    },
    {
     "grade": "8",
     "minMark": 68
    },
    {
     "grade": "7",
     "minMark": 58
    },
    {
     "grade": "6",
     "minMark": 48
    },
    {
     "grade": "5",
     "minMark": 39
    },
    {
     "grade": "4",
     "minMark": 30
    },
    {
     "grade": "3",
     "minMark": 21
    },
    {
     "grade": "2",
     "minMark": 13
    },
    {
     "grade": "1",
     "minMark": 5
    }
   ]
  ],
  "expect": {
   "grade": "9",
   "minMark": 78,
   "nextGrade": null,
   "marksToNext": null
  }
 },
 {
  "name": "one mark below a boundary is the grade beneath it",
  "args": [
   77,
   100,
   [
    {
     "grade": "9",
     "minMark": 78
    },
    {
     "grade": "8",
     "minMark": 68
    },
    {
     "grade": "7",
     "minMark": 58
    },
    {
     "grade": "6",
     "minMark": 48
    },
    {
     "grade": "5",
     "minMark": 39
    },
    {
     "grade": "4",
     "minMark": 30
    },
    {
     "grade": "3",
     "minMark": 21
    },
    {
     "grade": "2",
     "minMark": 13
    },
    {
     "grade": "1",
     "minMark": 5
    }
   ]
  ],
  "expect": {
   "grade": "8",
   "minMark": 68,
   "nextGrade": "9",
   "marksToNext": 1
  }
 },
 {
  "name": "full marks",
  "args": [
   100,
   100,
   [
    {
     "grade": "9",
     "minMark": 78
    },
    {
     "grade": "8",
     "minMark": 68
    },
    {
     "grade": "7",
     "minMark": 58
    },
    {
     "grade": "6",
     "minMark": 48
    },
    {
     "grade": "5",
     "minMark": 39
    },
    {
     "grade": "4",
     "minMark": 30
    },
    {
     "grade": "3",
     "minMark": 21
    },
    {
     "grade": "2",
     "minMark": 13
    },
    {
     "grade": "1",
     "minMark": 5
    }
   ]
  ],
  "expect": {
   "grade": "9",
   "minMark": 78,
   "nextGrade": null,
   "marksToNext": null
  }
 },
 {
  "name": "a mid-table mark, and the marks to the next grade",
  "args": [
   30,
   100,
   [
    {
     "grade": "9",
     "minMark": 78
    },
    {
     "grade": "8",
     "minMark": 68
    },
    {
     "grade": "7",
     "minMark": 58
    },
    {
     "grade": "6",
     "minMark": 48
    },
    {
     "grade": "5",
     "minMark": 39
    },
    {
     "grade": "4",
     "minMark": 30
    },
    {
     "grade": "3",
     "minMark": 21
    },
    {
     "grade": "2",
     "minMark": 13
    },
    {
     "grade": "1",
     "minMark": 5
    }
   ]
  ],
  "expect": {
   "grade": "4",
   "minMark": 30,
   "nextGrade": "5",
   "marksToNext": 9
  }
 },
 {
  "name": "one mark below the lowest boundary is ungraded",
  "args": [
   4,
   100,
   [
    {
     "grade": "9",
     "minMark": 78
    },
    {
     "grade": "8",
     "minMark": 68
    },
    {
     "grade": "7",
     "minMark": 58
    },
    {
     "grade": "6",
     "minMark": 48
    },
    {
     "grade": "5",
     "minMark": 39
    },
    {
     "grade": "4",
     "minMark": 30
    },
    {
     "grade": "3",
     "minMark": 21
    },
    {
     "grade": "2",
     "minMark": 13
    },
    {
     "grade": "1",
     "minMark": 5
    }
   ]
  ],
  "expect": {
   "grade": null,
   "minMark": null,
   "nextGrade": "1",
   "marksToNext": 1
  }
 },
 {
  "name": "zero is ungraded and the whole lowest boundary away",
  "args": [
   0,
   100,
   [
    {
     "grade": "9",
     "minMark": 78
    },
    {
     "grade": "8",
     "minMark": 68
    },
    {
     "grade": "7",
     "minMark": 58
    },
    {
     "grade": "6",
     "minMark": 48
    },
    {
     "grade": "5",
     "minMark": 39
    },
    {
     "grade": "4",
     "minMark": 30
    },
    {
     "grade": "3",
     "minMark": 21
    },
    {
     "grade": "2",
     "minMark": 13
    },
    {
     "grade": "1",
     "minMark": 5
    }
   ]
  ],
  "expect": {
   "grade": null,
   "minMark": null,
   "nextGrade": "1",
   "marksToNext": 5
  }
 },
 {
  "name": "a table in no particular order: 59 is a C, one short of a B, not the last row read",
  "args": [
   59,
   100,
   [
    {
     "grade": "C",
     "minMark": 50
    },
    {
     "grade": "A*",
     "minMark": 80
    },
    {
     "grade": "E",
     "minMark": 30
    },
    {
     "grade": "A",
     "minMark": 70
    },
    {
     "grade": "D",
     "minMark": 40
    },
    {
     "grade": "B",
     "minMark": 60
    }
   ]
  ],
  "expect": {
   "grade": "C",
   "minMark": 50,
   "nextGrade": "B",
   "marksToNext": 1
  }
 },
 {
  "name": "A* at its boundary in a shuffled table",
  "args": [
   80,
   100,
   [
    {
     "grade": "C",
     "minMark": 50
    },
    {
     "grade": "A*",
     "minMark": 80
    },
    {
     "grade": "E",
     "minMark": 30
    },
    {
     "grade": "A",
     "minMark": 70
    },
    {
     "grade": "D",
     "minMark": 40
    },
    {
     "grade": "B",
     "minMark": 60
    }
   ]
  ],
  "expect": {
   "grade": "A*",
   "minMark": 80,
   "nextGrade": null,
   "marksToNext": null
  }
 },
 {
  "name": "a lowest row at 0 means no mark is ungraded",
  "args": [
   0,
   100,
   [
    {
     "grade": "Distinction",
     "minMark": 70
    },
    {
     "grade": "Merit",
     "minMark": 60
    },
    {
     "grade": "Pass",
     "minMark": 40
    },
    {
     "grade": "Fail",
     "minMark": 0
    }
   ]
  ],
  "expect": {
   "grade": "Fail",
   "minMark": 0,
   "nextGrade": "Pass",
   "marksToNext": 40
  }
 },
 {
  "name": "a single-row table: pass at the boundary",
  "args": [
   50,
   50,
   [
    {
     "grade": "Pass",
     "minMark": 50
    }
   ]
  ],
  "expect": {
   "grade": "Pass",
   "minMark": 50,
   "nextGrade": null,
   "marksToNext": null
  }
 },
 {
  "name": "a single-row table: below it is ungraded",
  "args": [
   49,
   50,
   [
    {
     "grade": "Pass",
     "minMark": 50
    }
   ]
  ],
  "expect": {
   "grade": null,
   "minMark": null,
   "nextGrade": "Pass",
   "marksToNext": 1
  }
 },
 {
  "name": "a mark above maxMark is an error",
  "args": [
   101,
   100,
   [
    {
     "grade": "9",
     "minMark": 78
    },
    {
     "grade": "8",
     "minMark": 68
    },
    {
     "grade": "7",
     "minMark": 58
    },
    {
     "grade": "6",
     "minMark": 48
    },
    {
     "grade": "5",
     "minMark": 39
    },
    {
     "grade": "4",
     "minMark": 30
    },
    {
     "grade": "3",
     "minMark": 21
    },
    {
     "grade": "2",
     "minMark": 13
    },
    {
     "grade": "1",
     "minMark": 5
    }
   ]
  ],
  "expectError": "mark must be a whole number from 0 to maxMark (100)"
 },
 {
  "name": "a negative mark is an error",
  "args": [
   -1,
   100,
   [
    {
     "grade": "9",
     "minMark": 78
    },
    {
     "grade": "8",
     "minMark": 68
    },
    {
     "grade": "7",
     "minMark": 58
    },
    {
     "grade": "6",
     "minMark": 48
    },
    {
     "grade": "5",
     "minMark": 39
    },
    {
     "grade": "4",
     "minMark": 30
    },
    {
     "grade": "3",
     "minMark": 21
    },
    {
     "grade": "2",
     "minMark": 13
    },
    {
     "grade": "1",
     "minMark": 5
    }
   ]
  ],
  "expectError": "mark must be a whole number from 0 to maxMark (100)"
 },
 {
  "name": "a half mark is an error",
  "args": [
   12.5,
   100,
   [
    {
     "grade": "9",
     "minMark": 78
    },
    {
     "grade": "8",
     "minMark": 68
    },
    {
     "grade": "7",
     "minMark": 58
    },
    {
     "grade": "6",
     "minMark": 48
    },
    {
     "grade": "5",
     "minMark": 39
    },
    {
     "grade": "4",
     "minMark": 30
    },
    {
     "grade": "3",
     "minMark": 21
    },
    {
     "grade": "2",
     "minMark": 13
    },
    {
     "grade": "1",
     "minMark": 5
    }
   ]
  ],
  "expectError": "mark must be a whole number from 0 to maxMark (100)"
 },
 {
  "name": "maxMark of zero is an error",
  "args": [
   0,
   0,
   [
    {
     "grade": "9",
     "minMark": 78
    },
    {
     "grade": "8",
     "minMark": 68
    },
    {
     "grade": "7",
     "minMark": 58
    },
    {
     "grade": "6",
     "minMark": 48
    },
    {
     "grade": "5",
     "minMark": 39
    },
    {
     "grade": "4",
     "minMark": 30
    },
    {
     "grade": "3",
     "minMark": 21
    },
    {
     "grade": "2",
     "minMark": 13
    },
    {
     "grade": "1",
     "minMark": 5
    }
   ]
  ],
  "expectError": "maxMark must be a positive whole number"
 },
 {
  "name": "an empty table is an error",
  "args": [
   10,
   100,
   []
  ],
  "expectError": "boundaries must not be empty"
 },
 {
  "name": "a grade named twice is an error",
  "args": [
   10,
   100,
   [
    {
     "grade": "A",
     "minMark": 70
    },
    {
     "grade": "A",
     "minMark": 60
    }
   ]
  ],
  "expectError": "grade A appears twice in boundaries"
 },
 {
  "name": "two grades on one boundary is an error",
  "args": [
   10,
   100,
   [
    {
     "grade": "A",
     "minMark": 70
    },
    {
     "grade": "B",
     "minMark": 70
    }
   ]
  ],
  "expectError": "grades A and B share the boundary 70"
 },
 {
  "name": "a boundary above maxMark is an error",
  "args": [
   10,
   60,
   [
    {
     "grade": "9",
     "minMark": 78
    },
    {
     "grade": "8",
     "minMark": 68
    },
    {
     "grade": "7",
     "minMark": 58
    },
    {
     "grade": "6",
     "minMark": 48
    },
    {
     "grade": "5",
     "minMark": 39
    },
    {
     "grade": "4",
     "minMark": 30
    },
    {
     "grade": "3",
     "minMark": 21
    },
    {
     "grade": "2",
     "minMark": 13
    },
    {
     "grade": "1",
     "minMark": 5
    }
   ]
  ],
  "expectError": "boundary minMark must be a whole number from 0 to maxMark (60), received 78 for grade 9"
 },
 {
  "name": "an empty grade name is an error",
  "args": [
   10,
   100,
   [
    {
     "grade": "",
     "minMark": 70
    }
   ]
  ],
  "expectError": "every boundary needs a non-empty grade"
 }
]