improve test coverage

Signed-off-by: Ziqi Zhao <zhaoziqi9146@gmail.com>

exporters/prometheus/exporter_test.go

@@ -230,14 +230,33 @@ func TestPrometheusExporter(t *testing.T) {
 					attribute.Key("A").String("B"),
 					attribute.Key("C").String("D"),
 				}
-				gauge, err := meter.SyncFloat64().UpDownCounter(
+				gauge, err := meter.SyncInt64().UpDownCounter(
 					"bar",
 					instrument.WithDescription("a fun little gauge"),
 					instrument.WithUnit(unit.Dimensionless),
 				)
 				require.NoError(t, err)
-				gauge.Add(ctx, 1.0, attrs...)
-				gauge.Add(ctx, -.25, attrs...)
+				gauge.Add(ctx, 2, attrs...)
+				gauge.Add(ctx, -1, attrs...)
+			},
+		},
+		{
+			name:         "without scope_info and target_info",
+			options:      []Option{WithoutScopeInfo(), WithoutTargetInfo()},
+			expectedFile: "testdata/without_scope_and_target_info.txt",
+			recordMetrics: func(ctx context.Context, meter otelmetric.Meter) {
+				attrs := []attribute.KeyValue{
+					attribute.Key("A").String("B"),
+					attribute.Key("C").String("D"),
+				}
+				counter, err := meter.SyncInt64().Counter(
+					"bar",
+					instrument.WithDescription("a fun little counter"),
+					instrument.WithUnit(unit.Bytes),
+				)
+				require.NoError(t, err)
+				counter.Add(ctx, 2, attrs...)
+				counter.Add(ctx, 1, attrs...)
 			},
 		},
 	}

exporters/prometheus/testdata/without_scope_and_target_info.txt

@@ -0,0 +1,3 @@
+# HELP bar_bytes_total a fun little counter
+# TYPE bar_bytes_total counter
+bar_bytes_total{A="B",C="D"} 3

exporters/prometheus/testdata/without_scope_info.txt

@@ -1,6 +1,6 @@
 # HELP bar_ratio a fun little gauge
 # TYPE bar_ratio gauge
-bar_ratio{A="B",C="D"} .75
+bar_ratio{A="B",C="D"} 1
 # HELP target_info Target metadata
 # TYPE target_info gauge
 target_info{service_name="prometheus_test",telemetry_sdk_language="go",telemetry_sdk_name="opentelemetry",telemetry_sdk_version="latest"} 1