YTS test instructs how to download test data

In order to run the yaml test suite we need the data files to be
present. A user with a fresh clone trying to run all tests will face an
error. This makes the error message clear and provides the step needed
to enable the tests to run.

Author: carloslima

GNUmakefile

@@ -45,6 +45,8 @@ count ?= 1
 test: $(TEST-DEPS)
 	go test$(if $v, -v)
 
+test-data: $(YTS-DIR)
+
 test-all: test test-yts-all
 
 test-yts: $(TEST-DEPS)

yts/test_suite_test.go

@@ -49,6 +49,9 @@ func shouldSkipTest(t *testing.T) {
 
 func TestYAMLSuite(t *testing.T) {
 	testDir := "./testdata/data-2022-01-17"
+	if _, err := os.Stat(testDir + "/229Q"); os.IsNotExist(err) {
+		t.Fatalf("YTS tests requires the data files to be present in `%s`. Run `make test-data` to download them.", testDir)
+	}
 	runTestsInDir(t, testDir)
 }