public void Stopwatch_WhenMultipleOperations_ThenElapsedIncrements()
{
using (var trace = new TraceListenerScope())
{
var usable =
// Stopwatch usable starts counting the moment somebody calls Use().
from stopwatch in Usable.Stopwatch()
from outer in Usable.Using(() => new TraceSourceScope("outer"))
// Snapshot elapsed to know how long it took to instantiate outer.
let elapsedOuter = stopwatch.Elapsed
from inner in new TraceSourceScope("inner")
// Snapshot elapsed to know how long it took to instantiate inner.
let elapsedInner = stopwatch.Elapsed - elapsedOuter
// Snapshot elapsed to know how long it took for the entire operation.
let elapsedTotal = stopwatch.Elapsed
// Return computed value together with all the timing information.
select new
{
Value = string.Join('/', outer.Operation, inner.Operation, "value").Trace(),
ElapsedOuter = elapsedOuter,
ElapsedInner = elapsedInner,
ElapsedTotal = elapsedTotal,
};
var expectedTrace = new string[]
{
"Enter: outer",
" Enter: inner",
" Value: outer/inner/value",
" Leave: inner",
"Leave: outer",
};
Assert.Equal(new string[0], trace.ToLines());
var value = usable.Value();
Assert.Equal("outer/inner/value", value.Value);
Assert.True(value.ElapsedOuter < value.ElapsedTotal);
Assert.True(value.ElapsedInner < value.ElapsedTotal);
Assert.Equal(expectedTrace, trace.ToLines());
}
Assert.Equal(0, Trace.IndentLevel);
}