Add header flag test

Signed-off-by: Jacob Weinstock <[email protected]>

cmd/eksctl-anywhere/cmd/aflag/header_test.go

@@ -0,0 +1,35 @@
+package aflag
+
+import (
+	"net/http"
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+)
+
+func TestHeaderM(t *testing.T) {
+	tests := map[string]struct {
+		shouldErr bool
+		want      http.Header
+		input     string
+	}{
+		"success":            {want: map[string][]string{"A": {"1", "2", "3"}, "B": {"2"}, "C": {"4"}}, input: `A=1;2;3,B=2,C=4`},
+		"bad input format 1": {shouldErr: true, input: `abc`, want: http.Header{}},
+		"bad input format 2": {shouldErr: true, input: `abc=123;abd=345,`, want: http.Header{}},
+	}
+
+	for name, tc := range tests {
+		t.Run(name, func(t *testing.T) {
+			h := http.Header{}
+			got := NewHeader(&h)
+			if err := got.Set(tc.input); err != nil {
+				if !tc.shouldErr {
+					t.Fatal(err)
+				}
+			}
+			if diff := cmp.Diff(tc.want, h); diff != "" {
+				t.Fatalf("diff: %s", diff)
+			}
+		})
+	}
+}