Pr 311 2 (#312)

* Add a setup test for middleware/file

This fix adds a setup test for middleware/file so that there is
a basic coverage for the Corefile processing of middleware/file.

This fix is related to 308 (Will look into it).

Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

* middleware/file: use helper function for test

Fixup setup_test.go and use the test.TempFile function to make things
somewhat shorter.

Use clean up the use of testing.T in TempFile - it is not used.

middleware/file/setup_test.go

@@ -0,0 +1,65 @@
+package file
+
+import (
+	"testing"
+
+	"github.com/miekg/coredns/middleware/test"
+
+	"github.com/mholt/caddy"
+)
+
+func TestFileParse(t *testing.T) {
+	zoneFileName1, rm, err := test.TempFile(".", dbMiekNL)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer rm()
+
+	zoneFileName2, rm, err := test.TempFile(".", dbDnssexNLSigned)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer rm()
+
+	tests := []struct {
+		inputFileRules string
+		shouldErr      bool
+		expectedZones  Zones
+	}{
+		{
+			`file`,
+			true,
+			Zones{},
+		},
+		{
+			`file ` + zoneFileName1 + ` miek.nl.`,
+			false,
+			Zones{Names: []string{"miek.nl."}},
+		},
+		{
+			`file ` + zoneFileName2 + ` dnssex.nl.`,
+			false,
+			Zones{Names: []string{"dnssex.nl."}},
+		},
+	}
+
+	for i, test := range tests {
+		c := caddy.NewTestController("file", test.inputFileRules)
+		actualZones, err := fileParse(c)
+
+		if err == nil && test.shouldErr {
+			t.Fatalf("Test %d expected errors, but got no error", i)
+		} else if err != nil && !test.shouldErr {
+			t.Fatalf("Test %d expected no errors, but got '%v'", i, err)
+		} else {
+			if len(actualZones.Names) != len(test.expectedZones.Names) {
+				t.Fatalf("Test %d expected %v, got %v", i, test.expectedZones.Names, actualZones.Names)
+			}
+			for j, name := range test.expectedZones.Names {
+				if actualZones.Names[j] != name {
+					t.Fatalf("Test %d expected %v for %d th zone, got %v", i, name, j, actualZones.Names[j])
+				}
+			}
+		}
+	}
+}