deviceinfo: add tests for new parser (MR 4)

An earlier revision of this patch had test for invalid lines, but I
decided to remove it because deviceinfo is sourced by so many things in
pmOS that it should be /very/ obvious that there are invalid lines or
other garbage in the file.

I also tried to make the parser fairly forgiving if it does encounter
things that don't meet the deviceinfo "spec", so that mkinitfs will try
as hard as it can to make an initfs.

pkgs/deviceinfo/deviceinfo_test.go

@@ -0,0 +1,81 @@
+// Copyright 2021 Clayton Craft <clayton@craftyguy.net>
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package deviceinfo
+
+import (
+	"fmt"
+	"reflect"
+	"strings"
+	"testing"
+)
+
+// Test conversion of name to DeviceInfo struct field format
+func TestNameToField(t *testing.T) {
+	tables := []struct {
+		in       string
+		expected string
+	}{
+		{"deviceinfo_dtb", "Dtb"},
+		{"dtb", "Dtb"},
+		{"deviceinfo_modules_initfs", "ModulesInitfs"},
+		{"modules_initfs", "ModulesInitfs"},
+		{"deviceinfo_modules_initfs___", "ModulesInitfs"},
+	}
+
+	for _, table := range tables {
+		out := nameToField(table.in)
+		if out != table.expected {
+			t.Errorf("expected: %q, got: %q", table.expected, out)
+		}
+	}
+}
+
+// Test unmarshalling with lines in deviceinfo
+func TestUnmarshal(t *testing.T) {
+	tables := []struct {
+		// field is just used for reflection within the test, so it must be a
+		// valid DeviceInfo field
+		field    string
+		in       string
+		expected string
+	}{
+		{"ModulesInitfs", "deviceinfo_modules_initfs=\"panfrost foo bar bazz\"\n", "panfrost foo bar bazz"},
+		{"ModulesInitfs", "deviceinfo_modules_initfs=\"panfrost foo bar bazz\"", "panfrost foo bar bazz"},
+		// line with multiple '='
+		{"KernelCmdline",
+			"deviceinfo_kernel_cmdline=\"PMOS_NO_OUTPUT_REDIRECT fw_devlink=off nvme_core.default_ps_max_latency_us=5500 pcie_aspm.policy=performance\"\n",
+			"PMOS_NO_OUTPUT_REDIRECT fw_devlink=off nvme_core.default_ps_max_latency_us=5500 pcie_aspm.policy=performance"},
+		// empty option
+		{"ModulesInitfs", "deviceinfo_modules_initfs=\"\"\n", ""},
+		{"Dtb", "deviceinfo_dtb=\"freescale/imx8mq-librem5-r2 freescale/imx8mq-librem5-r3 freescale/imx8mq-librem5-r4\"\n",
+			"freescale/imx8mq-librem5-r2 freescale/imx8mq-librem5-r3 freescale/imx8mq-librem5-r4"},
+		// valid deviceinfo line, just not used in this module
+		{"", "deviceinfo_codename=\"pine64-pinebookpro\"", ""},
+		// line with comment at the end
+		{"MesaDriver", "deviceinfo_mesa_driver=\"panfrost\"  # this is a nice driver", "panfrost"},
+		{"", "# this is a comment!\n", ""},
+		// empty lines are fine
+		{"", "", ""},
+		// line with whitepace characters only
+		{"", " \t \n\r", ""},
+	}
+	var d DeviceInfo
+	for _, table := range tables {
+		testName := fmt.Sprintf("unmarshal::'%s':", strings.ReplaceAll(table.in, "\n", "\\n"))
+		if err := unmarshal(strings.NewReader(table.in), &d); err != nil {
+			t.Errorf("%s received an unexpected err: ", err)
+		}
+
+		// Check against expected value
+		field := reflect.ValueOf(&d).Elem().FieldByName(table.field)
+		out := ""
+		if table.field != "" {
+			out = field.String()
+		}
+		if out != table.expected {
+			t.Errorf("%s expected: %q, got: %q", testName, table.expected, out)
+		}
+	}
+
+}