Revamp testing console messages (get rid of exact indices)

[Cafe137]

During test runs, we put every console message (stdout of swarm-cli) to an array. To assert correct output, we check these messages by exact index to match a regex or contain some substring.

This is often annoying and causes off-by-one errors when an extra step is added that shifts the indices.

I propose to change this approach with a less strict helper function linesMatchOrdered which takes an array of expected substrings (or regexes) to appear in the output, respecting the order, but ignoring gaps and omitting the indices.

Before

expect(getNthLastMessage(3)).toContain('Utilization')
expect(getNthLastMessage(3)).toContain('0')
expect(getNthLastMessage(4)).toContain('Usable')
expect(getNthLastMessage(4)).toContain('true')
expect(getNthLastMessage(9)).toContain('Usage')
expect(getNthLastMessage(9)).toContain('0%')
expect(getNthLastMessage(10)).toContain('Label:')
expect(getNthLastMessage(10)).toContain('Alice')
expect(getNthLastMessage(11)).toContain('Stamp ID')
expect(getNthLastMessage(11)).toContain(id)

After

assert(linesMatchOrdered(consoleMessages, [
    `Stamp ID: ${id}`,
    `Label: Alice`,
    'Usage: 0%',
    'Usable: true',
    'Utilization: 0',
]))

Naive implementation

function linesMatchOrdered(lines, expectedLines) {
    let lineIndex = 0
    for (let i = 0; i < expectedLines.length; i++) {
        const expectedLine = expectedLines[i]
        let found = false
        while (!found && lineIndex < lines.length) {
            if (lines[lineIndex].includes(expectedLine)) {
                found = true
            }
            lineIndex++
        }
        if (!found) {
            return false
        }
    }
    return true
}