diff --git a/internal/flag/intslice_test.go b/internal/flag/intslice_test.go
new file mode 100644
index 0000000..6e890d5
--- /dev/null
+++ b/internal/flag/intslice_test.go
@@ -0,0 +1,56 @@
+package flag_test
+
+import (
+	"flag"
+	"testing"
+
+	internalFlag "codeflow.dananglin.me.uk/apollo/enbas/internal/flag"
+)
+
+func TestIntSliceValue(t *testing.T) {
+	flagset := flag.NewFlagSet("test", flag.ExitOnError)
+	intSliceVal := internalFlag.NewIntSliceValue()
+
+	if !intSliceVal.Empty() {
+		t.Fatalf("The initialised IntSliceValue is not empty")
+	}
+
+	flagset.Var(&intSliceVal, "int-value", "Integer value")
+
+	args := []string{
+		"--int-value", "0",
+		"--int-value", "1",
+		"--int-value", "2",
+		"--int-value", "3",
+		"--int-value", "4",
+	}
+
+	if err := flagset.Parse(args); err != nil {
+		t.Fatalf("Received an error parsing the flag: %v", err)
+	}
+
+	wantLength := 5
+	if !intSliceVal.ExpectedLength(wantLength) {
+		t.Fatalf(
+			"Error: intSliceVal.ExpectedLength(%d) == false: actual length is %d",
+			wantLength,
+			len(intSliceVal),
+		)
+	}
+
+	want := "0, 1, 2, 3, 4"
+	got := intSliceVal.String()
+
+	if got != want {
+		t.Errorf(
+			"Unexpected result after parsing IntSliceValue: want %s, got %s",
+			want,
+			got,
+		)
+	} else {
+		t.Logf(
+			"Expected result after parsing IntSliceValue: got %s",
+			got,
+		)
+	}
+}
diff --git a/internal/flag/stringslice_test.go b/internal/flag/stringslice_test.go
new file mode 100644
index 0000000..a6759e6
--- /dev/null
+++ b/internal/flag/stringslice_test.go
@@ -0,0 +1,57 @@
+package flag_test
+
+import (
+	"flag"
+	"testing"
+
+	internalFlag "codeflow.dananglin.me.uk/apollo/enbas/internal/flag"
+)
+
+func TestStringSliceValue(t *testing.T) {
+	flagset := flag.NewFlagSet("test", flag.ExitOnError)
+	stringSliceVal := internalFlag.NewStringSliceValue()
+
+	if !stringSliceVal.Empty() {
+		t.Fatalf("The initialised StringSliceValue is not empty")
+	}
+
+	flagset.Var(&stringSliceVal, "colour", "String value")
+
+	args := []string{
+		"--colour", "orange",
+		"--colour", "blue",
+		"--colour", "magenta",
+		"--colour", "red",
+		"--colour", "green",
+		"--colour", "silver",
+	}
+
+	if err := flagset.Parse(args); err != nil {
+		t.Fatalf("Received an error parsing the flag: %v", err)
+	}
+
+	wantLength := 6
+	if !stringSliceVal.ExpectedLength(wantLength) {
+		t.Fatalf(
+			"Error: intSliceVal.ExpectedLength(%d) == false: actual length is %d",
+			wantLength,
+			len(stringSliceVal),
+		)
+	}
+
+	want := "orange, blue, magenta, red, green, silver"
+	got := stringSliceVal.String()
+
+	if got != want {
+		t.Errorf(
+			"Unexpected result after parsing StringSliceValue: want %s, got %s",
+			want,
+			got,
+		)
+	} else {
+		t.Logf(
+			"Expected result after parsing StringSliceValue: got %s",
+			got,
+		)
+	}
+}