compareScenarios() needs its own test

[0UmfHxcvx5J7JoaOhFSs5mncnisTJJ6q]

remind2/tests/testthat/test-convGDX2mif.R

Lines 87 to 95 in 555634c

	message("Checking compareScenarios...")
	myMifs <- file.path(tempdir(), paste0(seq_len(numberOfMifs), ".mif"))
	histMif <- file.path(tempdir(), "historical.mif")
	if (!file.exists(histMif)) {
	utils::download.file("https://rse.pik-potsdam.de/data/example/historical.mif", histMif, quiet = TRUE)
	}
	scenarioComparisonPath <- file.path(tempdir(), "scenarioComparison.pdf")
	suppressWarnings(compareScenarios(myMifs, histMif, fileName = scenarioComparisonPath))
	expect_true(file.exists(scenarioComparisonPath))

going back to a749524

Having convGDX2MIF() and compareScenarios() in the same test gives not differentiation on which one failed.

@chroetz possibly extend to test compareScenarios2(), or remove the compareScenarios() test should we move to compareScenarios2() anyways (I sure hope so).