test(bench): measure the long document on the typed decode and marshal paths

The suite gains BenchmarkStrictDecodeLong and BenchmarkMarshalLong over the same 2000-entry document ParseLong uses, so long-input work is visible on every path, not the parse alone. docs/BENCHMARKING.md lists them.

bench_test.go

@@ -127,3 +127,44 @@ func BenchmarkParseLong(b *testing.B) {
 		}
 	}
 }
+
+// benchLongEntry mirrors one [[entry]] element of longDoc for the typed
+// decode of the long document.
+type benchLongEntry struct {
+	Name   string    `toml:"name"`
+	Weight int       `toml:"weight"`
+	When   time.Time `toml:"when"`
+	Ratio  float64   `toml:"ratio"`
+	Tags   []string  `toml:"tags"`
+}
+
+type benchLongDoc struct {
+	Title string           `toml:"title"`
+	Entry []benchLongEntry `toml:"entry"`
+}
+
+func BenchmarkStrictDecodeLong(b *testing.B) {
+	dec := NewDecoder().DisallowUnknownFields()
+	b.ReportAllocs()
+	b.SetBytes(int64(len(longDoc)))
+	for b.Loop() {
+		var doc benchLongDoc
+		if err := dec.Decode(longDoc, &doc); err != nil {
+			b.Fatal(err)
+		}
+	}
+}
+
+func BenchmarkMarshalLong(b *testing.B) {
+	tree, err := ParseMap(longDoc)
+	if err != nil {
+		b.Fatal(err)
+	}
+	b.ReportAllocs()
+	b.SetBytes(int64(len(longDoc)))
+	for b.Loop() {
+		if _, err := Marshal(tree); err != nil {
+			b.Fatal(err)
+		}
+	}
+}

docs/BENCHMARKING.md

@@ -9,10 +9,12 @@ The benchmarks live in `bench_test.go`, next to the code they measure:
 
 | Benchmark | What it measures |
 |---|---|
-| `BenchmarkParse` | `Parse` over a representative configuration document |
+| `BenchmarkParse` | `ParseMap` over a representative configuration document |
-| `BenchmarkMarshal` | `Marshal` of the tree `Parse` produced from the same document |
+| `BenchmarkMarshal` | `Marshal` of the tree `ParseMap` produced from the same document |
 | `BenchmarkStrictDecode` | `Decode` into a struct under `DisallowUnknownFields` |
-| `BenchmarkParseLong` | `Parse` over a generated document with about 2000 array-of-tables entries |
+| `BenchmarkParseLong` | `ParseMap` over a generated document with about 2000 array-of-tables entries |
+| `BenchmarkStrictDecodeLong` | `Decode` into a typed document under `DisallowUnknownFields`, over the same long document |
+| `BenchmarkMarshalLong` | `Marshal` of the tree `ParseMap` produced from the long document |
 
 ## Running