Copyright by Kent Beck

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Chapter 1. Multi-Currency Money

We'll start with the object that Ward created at WyCash, multi-currency money (refer to the Introduction). Suppose we have a report like this:

Instrument Shares Price Total
IBM 1000 25 25000
GE 400 100 40000
  Total 65000

To make a multi-currency report, we need to add currencies:

Instrument Shares Price Total
IBM 1000 25 USD 25000 USD
Novartis 400 150 CHF 60000 CHF
  Total 65000 USD

We also need to specify exchange rates:

From To Rate
CHF USD 1.5

What behavior will we need to produce the revised report? Put another way, what set of tests, when passed, will demonstrate the presence of code we are confident will compute the report correctly?

  • We need to be able to add amounts ...

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