Provided tests for functions that can be tested (Closes #20).

flags/validChar_test.go

@@ -0,0 +1,39 @@
+package flags
+
+import "testing"
+
+func TestValidChar(t *testing.T) {
+	tests := []struct {
+		name  string
+		char  rune
+		valid bool
+	}{
+		{
+			name:  "Valid char",
+			char:  '1',
+			valid: true,
+		},
+		{
+			name:  "Invalid char",
+			char:  'a',
+			valid: false,
+		},
+		{
+			name:  "Valid char but not relevant",
+			char:  '0',
+			valid: true,
+		},
+	}
+
+	flags := Flags{}
+
+	// Run tests
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := flags.validChar(tt.char); got != tt.valid {
+				t.Errorf("validChar() = %v, want %v", got, tt.valid)
+			}
+		})
+	}
+
+}