[
 {
  "name": "a 60/40 portfolio exactly on target",
  "args": [
   [
    {
     "id": "EQUITY",
     "value": {
      "minor": 600000,
      "currency": "GBP"
     },
     "targetBasisPoints": 6000
    },
    {
     "id": "BONDS",
     "value": {
      "minor": 400000,
      "currency": "GBP"
     },
     "targetBasisPoints": 4000
    }
   ]
  ],
  "expect": {
   "total": {
    "minor": 1000000,
    "currency": "GBP"
   },
   "holdings": [
    {
     "id": "EQUITY",
     "value": {
      "minor": 600000,
      "currency": "GBP"
     },
     "weightBasisPoints": 6000,
     "targetBasisPoints": 6000,
     "driftBasisPoints": 0,
     "targetValue": {
      "minor": 600000,
      "currency": "GBP"
     },
     "driftValue": {
      "minor": 0,
      "currency": "GBP"
     }
    },
    {
     "id": "BONDS",
     "value": {
      "minor": 400000,
      "currency": "GBP"
     },
     "weightBasisPoints": 4000,
     "targetBasisPoints": 4000,
     "driftBasisPoints": 0,
     "targetValue": {
      "minor": 400000,
      "currency": "GBP"
     },
     "driftValue": {
      "minor": 0,
      "currency": "GBP"
     }
    }
   ],
   "maxAbsDriftBasisPoints": 0
  }
 },
 {
  "name": "equities have run up to 70% against a 60% target",
  "args": [
   [
    {
     "id": "EQUITY",
     "value": {
      "minor": 700000,
      "currency": "GBP"
     },
     "targetBasisPoints": 6000
    },
    {
     "id": "BONDS",
     "value": {
      "minor": 300000,
      "currency": "GBP"
     },
     "targetBasisPoints": 4000
    }
   ]
  ],
  "expect": {
   "total": {
    "minor": 1000000,
    "currency": "GBP"
   },
   "holdings": [
    {
     "id": "EQUITY",
     "value": {
      "minor": 700000,
      "currency": "GBP"
     },
     "weightBasisPoints": 7000,
     "targetBasisPoints": 6000,
     "driftBasisPoints": 1000,
     "targetValue": {
      "minor": 600000,
      "currency": "GBP"
     },
     "driftValue": {
      "minor": 100000,
      "currency": "GBP"
     }
    },
    {
     "id": "BONDS",
     "value": {
      "minor": 300000,
      "currency": "GBP"
     },
     "weightBasisPoints": 3000,
     "targetBasisPoints": 4000,
     "driftBasisPoints": -1000,
     "targetValue": {
      "minor": 400000,
      "currency": "GBP"
     },
     "driftValue": {
      "minor": -100000,
      "currency": "GBP"
     }
    }
   ],
   "maxAbsDriftBasisPoints": 1000
  }
 },
 {
  "name": "three equal holdings are 3333 bp each and the weights do not sum to 10000",
  "args": [
   [
    {
     "id": "A",
     "value": {
      "minor": 100,
      "currency": "GBP"
     },
     "targetBasisPoints": 3333
    },
    {
     "id": "B",
     "value": {
      "minor": 100,
      "currency": "GBP"
     },
     "targetBasisPoints": 3333
    },
    {
     "id": "C",
     "value": {
      "minor": 100,
      "currency": "GBP"
     },
     "targetBasisPoints": 3334
    }
   ]
  ],
  "expect": {
   "total": {
    "minor": 300,
    "currency": "GBP"
   },
   "holdings": [
    {
     "id": "A",
     "value": {
      "minor": 100,
      "currency": "GBP"
     },
     "weightBasisPoints": 3333,
     "targetBasisPoints": 3333,
     "driftBasisPoints": 0,
     "targetValue": {
      "minor": 100,
      "currency": "GBP"
     },
     "driftValue": {
      "minor": 0,
      "currency": "GBP"
     }
    },
    {
     "id": "B",
     "value": {
      "minor": 100,
      "currency": "GBP"
     },
     "weightBasisPoints": 3333,
     "targetBasisPoints": 3333,
     "driftBasisPoints": 0,
     "targetValue": {
      "minor": 100,
      "currency": "GBP"
     },
     "driftValue": {
      "minor": 0,
      "currency": "GBP"
     }
    },
    {
     "id": "C",
     "value": {
      "minor": 100,
      "currency": "GBP"
     },
     "weightBasisPoints": 3333,
     "targetBasisPoints": 3334,
     "driftBasisPoints": -1,
     "targetValue": {
      "minor": 100,
      "currency": "GBP"
     },
     "driftValue": {
      "minor": 0,
      "currency": "GBP"
     }
    }
   ],
   "maxAbsDriftBasisPoints": 1
  }
 },
 {
  "name": "half a basis point rounds up for both holdings, so the weights sum to 10001",
  "args": [
   [
    {
     "id": "A",
     "value": {
      "minor": 1,
      "currency": "GBP"
     },
     "targetBasisPoints": 0
    },
    {
     "id": "B",
     "value": {
      "minor": 19999,
      "currency": "GBP"
     },
     "targetBasisPoints": 10000
    }
   ]
  ],
  "expect": {
   "total": {
    "minor": 20000,
    "currency": "GBP"
   },
   "holdings": [
    {
     "id": "A",
     "value": {
      "minor": 1,
      "currency": "GBP"
     },
     "weightBasisPoints": 1,
     "targetBasisPoints": 0,
     "driftBasisPoints": 1,
     "targetValue": {
      "minor": 0,
      "currency": "GBP"
     },
     "driftValue": {
      "minor": 1,
      "currency": "GBP"
     }
    },
    {
     "id": "B",
     "value": {
      "minor": 19999,
      "currency": "GBP"
     },
     "weightBasisPoints": 10000,
     "targetBasisPoints": 10000,
     "driftBasisPoints": -1,
     "targetValue": {
      "minor": 20000,
      "currency": "GBP"
     },
     "driftValue": {
      "minor": -1,
      "currency": "GBP"
     }
    }
   ],
   "maxAbsDriftBasisPoints": 1
  }
 },
 {
  "name": "drift comes from the exact values, not weight minus target: -0.5 bp is -1, not 1 - 1 = 0",
  "args": [
   [
    {
     "id": "A",
     "value": {
      "minor": 1,
      "currency": "GBP"
     },
     "targetBasisPoints": 1
    },
    {
     "id": "B",
     "value": {
      "minor": 19999,
      "currency": "GBP"
     },
     "targetBasisPoints": 9999
    }
   ]
  ],
  "expect": {
   "total": {
    "minor": 20000,
    "currency": "GBP"
   },
   "holdings": [
    {
     "id": "A",
     "value": {
      "minor": 1,
      "currency": "GBP"
     },
     "weightBasisPoints": 1,
     "targetBasisPoints": 1,
     "driftBasisPoints": -1,
     "targetValue": {
      "minor": 2,
      "currency": "GBP"
     },
     "driftValue": {
      "minor": -1,
      "currency": "GBP"
     }
    },
    {
     "id": "B",
     "value": {
      "minor": 19999,
      "currency": "GBP"
     },
     "weightBasisPoints": 10000,
     "targetBasisPoints": 9999,
     "driftBasisPoints": 1,
     "targetValue": {
      "minor": 19998,
      "currency": "GBP"
     },
     "driftValue": {
      "minor": 1,
      "currency": "GBP"
     }
    }
   ],
   "maxAbsDriftBasisPoints": 1
  }
 },
 {
  "name": "a new fund worth nothing yet is fully underweight",
  "args": [
   [
    {
     "id": "OLD",
     "value": {
      "minor": 500000,
      "currency": "GBP"
     },
     "targetBasisPoints": 5000
    },
    {
     "id": "NEW",
     "value": {
      "minor": 0,
      "currency": "GBP"
     },
     "targetBasisPoints": 5000
    }
   ]
  ],
  "expect": {
   "total": {
    "minor": 500000,
    "currency": "GBP"
   },
   "holdings": [
    {
     "id": "OLD",
     "value": {
      "minor": 500000,
      "currency": "GBP"
     },
     "weightBasisPoints": 10000,
     "targetBasisPoints": 5000,
     "driftBasisPoints": 5000,
     "targetValue": {
      "minor": 250000,
      "currency": "GBP"
     },
     "driftValue": {
      "minor": 250000,
      "currency": "GBP"
     }
    },
    {
     "id": "NEW",
     "value": {
      "minor": 0,
      "currency": "GBP"
     },
     "weightBasisPoints": 0,
     "targetBasisPoints": 5000,
     "driftBasisPoints": -5000,
     "targetValue": {
      "minor": 250000,
      "currency": "GBP"
     },
     "driftValue": {
      "minor": -250000,
      "currency": "GBP"
     }
    }
   ],
   "maxAbsDriftBasisPoints": 5000
  }
 },
 {
  "name": "a holding with a zero target is all drift",
  "args": [
   [
    {
     "id": "KEEP",
     "value": {
      "minor": 750000,
      "currency": "GBP"
     },
     "targetBasisPoints": 10000
    },
    {
     "id": "SELL",
     "value": {
      "minor": 250000,
      "currency": "GBP"
     },
     "targetBasisPoints": 0
    }
   ]
  ],
  "expect": {
   "total": {
    "minor": 1000000,
    "currency": "GBP"
   },
   "holdings": [
    {
     "id": "KEEP",
     "value": {
      "minor": 750000,
      "currency": "GBP"
     },
     "weightBasisPoints": 7500,
     "targetBasisPoints": 10000,
     "driftBasisPoints": -2500,
     "targetValue": {
      "minor": 1000000,
      "currency": "GBP"
     },
     "driftValue": {
      "minor": -250000,
      "currency": "GBP"
     }
    },
    {
     "id": "SELL",
     "value": {
      "minor": 250000,
      "currency": "GBP"
     },
     "weightBasisPoints": 2500,
     "targetBasisPoints": 0,
     "driftBasisPoints": 2500,
     "targetValue": {
      "minor": 0,
      "currency": "GBP"
     },
     "driftValue": {
      "minor": 250000,
      "currency": "GBP"
     }
    }
   ],
   "maxAbsDriftBasisPoints": 2500
  }
 },
 {
  "name": "values whose x10000 passes 2^53 stay exact",
  "args": [
   [
    {
     "id": "A",
     "value": {
      "minor": 900000000000000,
      "currency": "GBP"
     },
     "targetBasisPoints": 5000
    },
    {
     "id": "B",
     "value": {
      "minor": 100000000000000,
      "currency": "GBP"
     },
     "targetBasisPoints": 5000
    }
   ]
  ],
  "expect": {
   "total": {
    "minor": 1000000000000000,
    "currency": "GBP"
   },
   "holdings": [
    {
     "id": "A",
     "value": {
      "minor": 900000000000000,
      "currency": "GBP"
     },
     "weightBasisPoints": 9000,
     "targetBasisPoints": 5000,
     "driftBasisPoints": 4000,
     "targetValue": {
      "minor": 500000000000000,
      "currency": "GBP"
     },
     "driftValue": {
      "minor": 400000000000000,
      "currency": "GBP"
     }
    },
    {
     "id": "B",
     "value": {
      "minor": 100000000000000,
      "currency": "GBP"
     },
     "weightBasisPoints": 1000,
     "targetBasisPoints": 5000,
     "driftBasisPoints": -4000,
     "targetValue": {
      "minor": 500000000000000,
      "currency": "GBP"
     },
     "driftValue": {
      "minor": -400000000000000,
      "currency": "GBP"
     }
    }
   ],
   "maxAbsDriftBasisPoints": 4000
  }
 },
 {
  "name": "a single holding is the whole portfolio",
  "args": [
   [
    {
     "id": "ONLY",
     "value": {
      "minor": 12345,
      "currency": "GBP"
     },
     "targetBasisPoints": 10000
    }
   ]
  ],
  "expect": {
   "total": {
    "minor": 12345,
    "currency": "GBP"
   },
   "holdings": [
    {
     "id": "ONLY",
     "value": {
      "minor": 12345,
      "currency": "GBP"
     },
     "weightBasisPoints": 10000,
     "targetBasisPoints": 10000,
     "driftBasisPoints": 0,
     "targetValue": {
      "minor": 12345,
      "currency": "GBP"
     },
     "driftValue": {
      "minor": 0,
      "currency": "GBP"
     }
    }
   ],
   "maxAbsDriftBasisPoints": 0
  }
 },
 {
  "name": "a third of a basis point rounds down both ways",
  "args": [
   [
    {
     "id": "A",
     "value": {
      "minor": 33333,
      "currency": "GBP"
     },
     "targetBasisPoints": 3000
    },
    {
     "id": "B",
     "value": {
      "minor": 66667,
      "currency": "GBP"
     },
     "targetBasisPoints": 7000
    }
   ]
  ],
  "expect": {
   "total": {
    "minor": 100000,
    "currency": "GBP"
   },
   "holdings": [
    {
     "id": "A",
     "value": {
      "minor": 33333,
      "currency": "GBP"
     },
     "weightBasisPoints": 3333,
     "targetBasisPoints": 3000,
     "driftBasisPoints": 333,
     "targetValue": {
      "minor": 30000,
      "currency": "GBP"
     },
     "driftValue": {
      "minor": 3333,
      "currency": "GBP"
     }
    },
    {
     "id": "B",
     "value": {
      "minor": 66667,
      "currency": "GBP"
     },
     "weightBasisPoints": 6667,
     "targetBasisPoints": 7000,
     "driftBasisPoints": -333,
     "targetValue": {
      "minor": 70000,
      "currency": "GBP"
     },
     "driftValue": {
      "minor": -3333,
      "currency": "GBP"
     }
    }
   ],
   "maxAbsDriftBasisPoints": 333
  }
 },
 {
  "name": "an empty portfolio is an error",
  "args": [
   []
  ],
  "expectError": "holdings must not be empty"
 },
 {
  "name": "the same id twice is an error",
  "args": [
   [
    {
     "id": "A",
     "value": {
      "minor": 1,
      "currency": "GBP"
     },
     "targetBasisPoints": 5000
    },
    {
     "id": "A",
     "value": {
      "minor": 1,
      "currency": "GBP"
     },
     "targetBasisPoints": 5000
    }
   ]
  ],
  "expectError": "duplicate holding id \"A\""
 },
 {
  "name": "targets summing to 9999 are an error",
  "args": [
   [
    {
     "id": "A",
     "value": {
      "minor": 1,
      "currency": "GBP"
     },
     "targetBasisPoints": 5000
    },
    {
     "id": "B",
     "value": {
      "minor": 1,
      "currency": "GBP"
     },
     "targetBasisPoints": 4999
    }
   ]
  ],
  "expectError": "targets must sum to 10000 basis points, received 9999"
 },
 {
  "name": "mixed currencies are an error",
  "args": [
   [
    {
     "id": "A",
     "value": {
      "minor": 1,
      "currency": "GBP"
     },
     "targetBasisPoints": 5000
    },
    {
     "id": "B",
     "value": {
      "minor": 1,
      "currency": "USD"
     },
     "targetBasisPoints": 5000
    }
   ]
  ],
  "expectError": "currency mismatch: GBP and USD"
 },
 {
  "name": "a negative value is an error",
  "args": [
   [
    {
     "id": "A",
     "value": {
      "minor": -1,
      "currency": "GBP"
     },
     "targetBasisPoints": 5000
    },
    {
     "id": "B",
     "value": {
      "minor": 10,
      "currency": "GBP"
     },
     "targetBasisPoints": 5000
    }
   ]
  ],
  "expectError": "holding values must be whole minor units, 0 or more"
 },
 {
  "name": "a fractional minor unit is an error",
  "args": [
   [
    {
     "id": "A",
     "value": {
      "minor": 1.5,
      "currency": "GBP"
     },
     "targetBasisPoints": 5000
    },
    {
     "id": "B",
     "value": {
      "minor": 10,
      "currency": "GBP"
     },
     "targetBasisPoints": 5000
    }
   ]
  ],
  "expectError": "holding values must be whole minor units, 0 or more"
 },
 {
  "name": "a target above 10000 is an error even if the sum works out",
  "args": [
   [
    {
     "id": "A",
     "value": {
      "minor": 1,
      "currency": "GBP"
     },
     "targetBasisPoints": 10001
    },
    {
     "id": "B",
     "value": {
      "minor": 1,
      "currency": "GBP"
     },
     "targetBasisPoints": -1
    }
   ]
  ],
  "expectError": "targetBasisPoints must be a whole number from 0 to 10000"
 },
 {
  "name": "a fractional target is an error",
  "args": [
   [
    {
     "id": "A",
     "value": {
      "minor": 1,
      "currency": "GBP"
     },
     "targetBasisPoints": 2500.5
    },
    {
     "id": "B",
     "value": {
      "minor": 1,
      "currency": "GBP"
     },
     "targetBasisPoints": 7499.5
    }
   ]
  ],
  "expectError": "targetBasisPoints must be a whole number from 0 to 10000"
 },
 {
  "name": "a portfolio worth nothing is an error",
  "args": [
   [
    {
     "id": "A",
     "value": {
      "minor": 0,
      "currency": "GBP"
     },
     "targetBasisPoints": 5000
    },
    {
     "id": "B",
     "value": {
      "minor": 0,
      "currency": "GBP"
     },
     "targetBasisPoints": 5000
    }
   ]
  ],
  "expectError": "the portfolio total must be greater than zero"
 }
]