Move ConsumeAndLogOutput to integration/utils.go

This will be used also by non-signing tests.

No code changes besides removing the initial capital letter in the
function name; this is a separate commit only to make reviewing of
future changes to this function easier.

integration/utils.go

@@ -0,0 +1,27 @@
+package main
+
+import (
+	"io"
+
+	"github.com/go-check/check"
+)
+
+// consumeAndLogOutput takes (f, err) from an exec.*Pipe(), and causes all output to it to be logged to c.
+func consumeAndLogOutput(c *check.C, id string, f io.ReadCloser, err error) {
+	c.Assert(err, check.IsNil)
+	go func() {
+		defer func() {
+			f.Close()
+			c.Logf("Output %s: Closed", id)
+		}()
+		buf := make([]byte, 0, 1024)
+		for {
+			c.Logf("Output %s: waiting", id)
+			n, err := f.Read(buf)
+			c.Logf("Output %s: got %d,%#v: %#v", id, n, err, buf[:n])
+			if n <= 0 {
+				break
+			}
+		}
+	}()
+}