StatsLogReader

auto data = new Array(
    "2018-09-12 10:03:07,598 2018-09-12 10:03:07,598 cpu_usage:1 memory:3\n" ~
    "2018-09-12 10:03:07,598 2018-09-12 10:03:07,598 cpu_usage:2 memory:4\n".dup);

auto reader = new StatsLogReader(data);

/// Iteration without index
size_t index;
foreach (line; reader)
{
    if (index == 0)
    {
        test!("==")(line["cpu_usage"], "1");
        test!("==")(line["memory"], "3");
    }
    else
    {
        test!("==")(line["cpu_usage"], "2");
        test!("==")(line["memory"], "4");
    }
    index++;
}

test!("==")(index, 2);

/// Iteration with index
data = new Array(
    "2018-09-12 10:03:07,598 2018-09-12 10:03:07,598 cpu_usage:1 memory:3\n" ~
    "2018-09-12 10:03:07,598 2018-09-12 10:03:07,598 cpu_usage:2 memory:4\n".dup);
reader = new StatsLogReader(data);
index = 0;
foreach (i, line; reader)
{
    if (i == 0)
    {
        test!("==")(line["cpu_usage"], "1");
        test!("==")(line["memory"], "3");
    }
    else
    {
        test!("==")(line["cpu_usage"], "2");
        test!("==")(line["memory"], "4");
    }

    index = i;
}

test!("==")(index, 1);

auto data = new Array(
    "2018-09-12 10:03:07,598 2018-09-12 10:03:07,598 cpu_usage:1 memory:3\n" ~
    "2018-09-12 10:03:07,598 2018-09-12 10:03:07,598 cpu_usage:2 memory:4\n".dup);

/// It should be able to get the last line with a function call
auto reader = new StatsLogReader(data);
auto line = reader.last();

test!("==")(line["cpu_usage"], "2");
test!("==")(line["memory"], "4");

/// It should raise an error for an empty string
data = new Array("".dup);
reader = new StatsLogReader(data);

testThrown!(Exception)(reader.last());