ruby_cover_band VS Sonic-Pi-Examples

A guitar is a string instrument, and each of those strings make a sound when you play them. For this example we'll focus on the happy path, which is that plucking the string plays the expected note. The code I built also considers that strings can break, and attempting to play broken strings won't work. You can look at the full implementation to see how that works.

In the earlier post on dependency injection, I created a PracticeAmplifier class that did nothing so I could use it in tests, rather than the "regular" amplifier.

In this example, our synthesizer changes its memory capabilities based on the brand that it is.

In reality, the difficulty in testing the Guitar class is what led to the decision to inject the amplifier in. That's because the Amplifier class is essentially a wrapper around Sonic Pi. Sonic Pi describes itself as a "code-based music creation and performance tool", so playing the guitar with this amplifier will actually play a sound on your computer.

We'll then take all of those notes and pass them to our amplifier, using Sonic Pi's play_pattern_timed method. This also allows us to define a time between each note, so we can place a small amount of time in between each to simulate the time it would take your hand to complete a downstroke across all the strings.