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/proc_io_test.go

@@ -0,0 +1,46 @@
+// 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 TestProcIO(t *testing.T) {
+	p, err := FS("fixtures").NewProc(26231)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	s, err := p.NewIO()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	for _, test := range []struct {
+		name string
+		want int64
+		have int64
+	}{
+		{name: "RChar", want: 750339, have: int64(s.RChar)},
+		{name: "WChar", want: 818609, have: int64(s.WChar)},
+		{name: "SyscR", want: 7405, have: int64(s.SyscR)},
+		{name: "SyscW", want: 5245, have: int64(s.SyscW)},
+		{name: "ReadBytes", want: 1024, have: int64(s.ReadBytes)},
+		{name: "WriteBytes", want: 2048, have: int64(s.WriteBytes)},
+		{name: "CancelledWriteBytes", want: -1024, have: s.CancelledWriteBytes},
+	} {
+		if test.want != test.have {
+			t.Errorf("want %s %d, have %d", test.name, test.want, test.have)
+		}
+	}
+}