promql: use subtests in TestLexer

Signed-off-by: Matt Layher <mdlayher@gmail.com>

promql/lex_test.go

@@ -19,13 +19,20 @@ import (
 	"testing"
 )
 
-var tests = []struct {
+type testCase struct {
 	input      string
 	expected   []item
 	fail       bool
 	seriesDesc bool // Whether to lex a series description.
+}
+
+var tests = []struct {
+	name  string
+	tests []testCase
 }{
-	// Test common stuff.
+	{
+		name: "common",
+		tests: []testCase{
 			{
 				input:    ",",
 				expected: []item{{itemComma, 0, ","}},
@@ -46,7 +53,11 @@ var tests = []struct {
 				input:    "\r\n\r",
 				expected: []item{},
 			},
-	// Test numbers.
+		},
+	},
+	{
+		name: "numbers",
+		tests: []testCase{
 			{
 				input:    "1",
 				expected: []item{{itemNumber, 0, "1"}},
@@ -99,7 +110,11 @@ var tests = []struct {
 				input:    "0x123",
 				expected: []item{{itemNumber, 0, "0x123"}},
 			},
-	// Test strings.
+		},
+	},
+	{
+		name: "strings",
+		tests: []testCase{
 			{
 				input:    "\"test\\tsequence\"",
 				expected: []item{{itemString, 0, `"test\tsequence"`}},
@@ -124,7 +139,11 @@ var tests = []struct {
 				input: ".٩",
 				fail:  true,
 			},
-	// Test duration.
+		},
+	},
+	{
+		name: "durations",
+		tests: []testCase{
 			{
 				input:    "5s",
 				expected: []item{{itemDuration, 0, "5s"}},
@@ -141,7 +160,11 @@ var tests = []struct {
 				input:    "1y",
 				expected: []item{{itemDuration, 0, "1y"}},
 			},
-	// Test identifiers.
+		},
+	},
+	{
+		name: "identifiers",
+		tests: []testCase{
 			{
 				input:    "abc",
 				expected: []item{{itemIdentifier, 0, "abc"}},
@@ -158,7 +181,11 @@ var tests = []struct {
 				input: "0a:bc",
 				fail:  true,
 			},
-	// Test comments.
+		},
+	},
+	{
+		name: "comments",
+		tests: []testCase{
 			{
 				input:    "# some comment",
 				expected: []item{{itemComment, 0, "# some comment"}},
@@ -170,7 +197,11 @@ var tests = []struct {
 					{itemNumber, 8, "5"},
 				},
 			},
-	// Test operators.
+		},
+	},
+	{
+		name: "operators",
+		tests: []testCase{
 			{
 				input:    `=`,
 				expected: []item{{itemAssign, 0, `=`}},
@@ -224,7 +255,11 @@ var tests = []struct {
 				input:    `unless`,
 				expected: []item{{itemLUnless, 0, `unless`}},
 			},
-	// Test aggregators.
+		},
+	},
+	{
+		name: "aggregators",
+		tests: []testCase{
 			{
 				input:    `sum`,
 				expected: []item{{itemSum, 0, `sum`}},
@@ -247,7 +282,11 @@ var tests = []struct {
 				input:    `stddev`,
 				expected: []item{{itemStddev, 0, `stddev`}},
 			},
-	// Test keywords.
+		},
+	},
+	{
+		name: "keywords",
+		tests: []testCase{
 			{
 				input:    "offset",
 				expected: []item{{itemOffset, 0, "offset"}},
@@ -273,7 +312,11 @@ var tests = []struct {
 				input:    "bool",
 				expected: []item{{itemBool, 0, "bool"}},
 			},
-	// Test Selector.
+		},
+	},
+	{
+		name: "selectors",
+		tests: []testCase{
 			{
 				input: `台北`,
 				fail:  true,
@@ -342,7 +385,11 @@ var tests = []struct {
 			}, {
 				input: `{foo:a="bar"}`, fail: true,
 			},
-	// Test common errors.
+		},
+	},
+	{
+		name: "common errors",
+		tests: []testCase{
 			{
 				input: `=~`, fail: true,
 			}, {
@@ -352,7 +399,11 @@ var tests = []struct {
 			}, {
 				input: "1a", fail: true,
 			},
-	// Test mismatched parens.
+		},
+	},
+	{
+		name: "mismatched parentheses",
+		tests: []testCase{
 			{
 				input: `(`, fail: true,
 			}, {
@@ -378,14 +429,22 @@ var tests = []struct {
 			}, {
 				input: `]`, fail: true,
 			},
-	// Test encoding issues.
+		},
+	},
+	{
+		name: "encoding issues",
+		tests: []testCase{
 			{
 				input: "\"\xff\"", fail: true,
 			},
 			{
 				input: "`\xff`", fail: true,
 			},
-	// Test series description.
+		},
+	},
+	{
+		name: "series descriptions",
+		tests: []testCase{
 			{
 				input: `{} _ 1 x .3`,
 				expected: []item{
@@ -429,7 +488,11 @@ var tests = []struct {
 				},
 				seriesDesc: true,
 			},
-	// Test subquery.
+		},
+	},
+	{
+		name: "subqueries",
+		tests: []testCase{
 			{
 				input: `test_name{on!~"bar"}[4m:4s]`,
 				expected: []item{
@@ -590,12 +653,16 @@ var tests = []struct {
 				input: `test:name{on!~"bar"}[:4s]`,
 				fail:  true,
 			},
+		},
+	},
 }
 
 // TestLexer tests basic functionality of the lexer. More elaborate tests are implemented
 // for the parser to avoid duplicated effort.
 func TestLexer(t *testing.T) {
-	for i, test := range tests {
+	for _, typ := range tests {
+		t.Run(typ.name, func(t *testing.T) {
+			for i, test := range typ.tests {
 				l := &lexer{
 					input:      test.input,
 					items:      make(chan item),
@@ -631,6 +698,8 @@ func TestLexer(t *testing.T) {
 					t.Fatalf("lexing mismatch:\nexpected:\n%s\ngot:\n%s", expectedList(test.expected), expectedList(out))
 				}
 			}
+		})
+	}
 }
 
 func expectedList(exp []item) string {