An OTDR (Optical Time Domain Reflectometer) Will tell you how long the fiber is, within a certain resolution (frequently to the closest meter, some will do half meter) ... and is useful for finding the approximate location of a break, or the length of the run.
For quality measurements, you'd use either a calibrated source and power meter and/or a Optical Spectrum Analyzer.
When the fiber is/was installed (if it was installed by a professional), they do a power measurement for the span and record & report it to the consumer.
With your own source & meter, you can compare the original reading to "what you got now" and determine if there is a significant degradation (dirt, crud, break, tight bend, etc).
With a spectrum analyzer, you can see how much spectral dispersion your span is producing and the basic quality of your pulse train / signal.
Sometimes several functions are integrated into a single device (JDSU does this, Fluke probably does too)
Another useful tools is a Visual Fault Locator, which puts a very bright red light down the fiber. When the light hits a break, it scatters the light and you see a red blip from the fiber's sheath.
Good Luck
Scott
