scrape: in tests use labels.FromStrings

And a few cases of `EmptyLabels()`.
Replacing code which assumes the internal structure of `Labels`.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>

scrape/manager_test.go

@@ -149,8 +149,8 @@ func TestPopulateLabels(t *testing.T) {
 				ScrapeInterval: model.Duration(time.Second),
 				ScrapeTimeout:  model.Duration(time.Second),
 			},
-			res:     nil,
+			res:     labels.EmptyLabels(),
-			resOrig: nil,
+			resOrig: labels.EmptyLabels(),
 			err:     "no address",
 		},
 		// Address label missing, but added in relabelling.
@@ -242,8 +242,8 @@ func TestPopulateLabels(t *testing.T) {
 				ScrapeInterval: model.Duration(time.Second),
 				ScrapeTimeout:  model.Duration(time.Second),
 			},
-			res:     nil,
+			res:     labels.EmptyLabels(),
-			resOrig: nil,
+			resOrig: labels.EmptyLabels(),
 			err:     "invalid label value for \"custom\": \"\\xbd\"",
 		},
 		// Invalid duration in interval label.
@@ -259,8 +259,8 @@ func TestPopulateLabels(t *testing.T) {
 				ScrapeInterval: model.Duration(time.Second),
 				ScrapeTimeout:  model.Duration(time.Second),
 			},
-			res:     nil,
+			res:     labels.EmptyLabels(),
-			resOrig: nil,
+			resOrig: labels.EmptyLabels(),
 			err:     "error parsing scrape interval: not a valid duration string: \"2notseconds\"",
 		},
 		// Invalid duration in timeout label.
@@ -276,8 +276,8 @@ func TestPopulateLabels(t *testing.T) {
 				ScrapeInterval: model.Duration(time.Second),
 				ScrapeTimeout:  model.Duration(time.Second),
 			},
-			res:     nil,
+			res:     labels.EmptyLabels(),
-			resOrig: nil,
+			resOrig: labels.EmptyLabels(),
 			err:     "error parsing scrape timeout: not a valid duration string: \"2notseconds\"",
 		},
 		// 0 interval in timeout label.
@@ -293,8 +293,8 @@ func TestPopulateLabels(t *testing.T) {
 				ScrapeInterval: model.Duration(time.Second),
 				ScrapeTimeout:  model.Duration(time.Second),
 			},
-			res:     nil,
+			res:     labels.EmptyLabels(),
-			resOrig: nil,
+			resOrig: labels.EmptyLabels(),
 			err:     "scrape interval cannot be 0",
 		},
 		// 0 duration in timeout label.
@@ -310,8 +310,8 @@ func TestPopulateLabels(t *testing.T) {
 				ScrapeInterval: model.Duration(time.Second),
 				ScrapeTimeout:  model.Duration(time.Second),
 			},
-			res:     nil,
+			res:     labels.EmptyLabels(),
-			resOrig: nil,
+			resOrig: labels.EmptyLabels(),
 			err:     "scrape timeout cannot be 0",
 		},
 		// Timeout less than interval.
@@ -328,8 +328,8 @@ func TestPopulateLabels(t *testing.T) {
 				ScrapeInterval: model.Duration(time.Second),
 				ScrapeTimeout:  model.Duration(time.Second),
 			},
-			res:     nil,
+			res:     labels.EmptyLabels(),
-			resOrig: nil,
+			resOrig: labels.EmptyLabels(),
 			err:     "scrape timeout cannot be greater than scrape interval (\"2s\" > \"1s\")",
 		},
 		// Don't attach default port.

scrape/scrape_test.go

@@ -116,22 +116,12 @@ func TestDiscoveredLabelsUpdate(t *testing.T) {
 	}
 	sp.activeTargets = make(map[uint64]*Target)
 	t1 := &Target{
-		discoveredLabels: labels.Labels{
+		discoveredLabels: labels.FromStrings("label", "name"),
-			labels.Label{
-				Name:  "label",
-				Value: "name",
-			},
-		},
 	}
 	sp.activeTargets[t1.hash()] = t1
 
 	t2 := &Target{
-		discoveredLabels: labels.Labels{
+		discoveredLabels: labels.FromStrings("labelNew", "nameNew"),
-			labels.Label{
-				Name:  "labelNew",
-				Value: "nameNew",
-			},
-		},
 	}
 	sp.sync([]*Target{t2})
 
@@ -1587,7 +1577,7 @@ func TestScrapeLoopAppendSampleLimit(t *testing.T) {
 		nil, nil, nil,
 		func(l labels.Labels) labels.Labels {
 			if l.Has("deleteme") {
-				return nil
+				return labels.EmptyLabels()
 			}
 			return l
 		},
@@ -2517,7 +2507,7 @@ func TestScrapeLoopDiscardUnnamedMetrics(t *testing.T) {
 		nil, nil,
 		func(l labels.Labels) labels.Labels {
 			if l.Has("drop") {
-				return labels.Labels{}
+				return labels.FromStrings("no", "name") // This label set will trigger an error.
 			}
 			return l
 		},
@@ -2628,20 +2618,7 @@ func TestReuseScrapeCache(t *testing.T) {
 		}
 		sp, _ = newScrapePool(cfg, app, 0, nil, &Options{})
 		t1    = &Target{
-			discoveredLabels: labels.Labels{
+			discoveredLabels: labels.FromStrings("labelNew", "nameNew", "labelNew1", "nameNew1", "labelNew2", "nameNew2"),
-				labels.Label{
-					Name:  "labelNew",
-					Value: "nameNew",
-				},
-				labels.Label{
-					Name:  "labelNew1",
-					Value: "nameNew1",
-				},
-				labels.Label{
-					Name:  "labelNew2",
-					Value: "nameNew2",
-				},
-			},
 		}
 		proxyURL, _ = url.Parse("http://localhost:2128")
 	)
@@ -2841,12 +2818,7 @@ func TestReuseCacheRace(t *testing.T) {
 		}
 		sp, _ = newScrapePool(cfg, app, 0, nil, &Options{})
 		t1    = &Target{
-			discoveredLabels: labels.Labels{
+			discoveredLabels: labels.FromStrings("labelNew", "nameNew"),
-				labels.Label{
-					Name:  "labelNew",
-					Value: "nameNew",
-				},
-			},
 		}
 	)
 	defer sp.stop()