Initial delivery of metrics code (#81)

* Initial delivery of metrics code

* Fix build issues

* Fix build issue with go vet

vendor/github.com/prometheus/procfs/mdstat_test.go

@@ -0,0 +1,44 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procfs
+
+import (
+	"testing"
+)
+
+func TestMDStat(t *testing.T) {
+	mdStates, err := FS("fixtures").ParseMDStat()
+	if err != nil {
+		t.Fatalf("parsing of reference-file failed entirely: %s", err)
+	}
+
+	refs := map[string]MDStat{
+		"md3":   {"md3", "active", 8, 8, 5853468288, 5853468288},
+		"md127": {"md127", "active", 2, 2, 312319552, 312319552},
+		"md0":   {"md0", "active", 2, 2, 248896, 248896},
+		"md4":   {"md4", "inactive", 2, 2, 4883648, 4883648},
+		"md6":   {"md6", "active", 1, 2, 195310144, 16775552},
+		"md8":   {"md8", "active", 2, 2, 195310144, 16775552},
+		"md7":   {"md7", "active", 3, 4, 7813735424, 7813735424},
+	}
+
+	if want, have := len(refs), len(mdStates); want != have {
+		t.Errorf("want %d parsed md-devices, have %d", want, have)
+	}
+	for _, md := range mdStates {
+		if want, have := refs[md.Name], md; want != have {
+			t.Errorf("%s: want %v, have %v", md.Name, want, have)
+		}
+	}
+}