test: unit tests for content facts, field type request options, variant keys and WebP

- pact: the content kinds and tools, zero facts, the value types
- cabana: mergeRequestOptions precedence, one call per type, fail-open,
  no shared maps
- attach: VariantKey on thumbnail names
- attach/webp: every image kind, the stored content type, the
  broken-image thumbnail and a refused mode

modules/lagoon/attach/variant_test.go

@@ -0,0 +1,51 @@
+package attach
+
+import (
+	"strings"
+	"testing"
+)
+
+// TestVariantKeyTable pins VariantKey beside ThumbKey's names: the
+// extension is replaced (case-insensitively, the format lower-cased), a key
+// with the format's extension gets it appended, a key without an extension
+// gets one, only the last extension counts, and a format outside the token
+// rule or an empty key answers "". A variant never equals its thumbnail.
+func TestVariantKeyTable(t *testing.T) {
+	for _, tc := range []struct{ thumb, format, want string }{
+		{"a/b/c/thumb_1_480_0_0_0_auto.jpg", "webp", "a/b/c/thumb_1_480_0_0_0_auto.webp"},
+		{"a/b/c/thumb_1_480_0_0_0_auto.JPG", "webp", "a/b/c/thumb_1_480_0_0_0_auto.webp"},
+		{"a/b/c/thumb_1_480_0_0_0_auto.jpeg", "AVIF", "a/b/c/thumb_1_480_0_0_0_auto.avif"},
+		{"a/b/c/thumb_1_480_0_0_0_auto.WEBP", "webp", "a/b/c/thumb_1_480_0_0_0_auto.WEBP.webp"},
+		{"a/b/c/thumb_1_480_0_0_0_auto.tar.gz", "webp", "a/b/c/thumb_1_480_0_0_0_auto.tar.webp"},
+		{"a/b/c/thumb_1_480_0_0_0_auto", "webp", "a/b/c/thumb_1_480_0_0_0_auto.webp"},
+		{"a/b.c/thumb", "webp", "a/b.c/thumb.webp"},
+		{"a/b/c/thumb_1.jpg", "web p", ""},
+		{"a/b/c/thumb_1.jpg", "webp/", ""},
+		{"a/b/c/thumb_1.jpg", "-", ""},
+		{"", "jpg", ""},
+	} {
+		got := VariantKey(tc.thumb, tc.format)
+		if got != tc.want {
+			t.Errorf("VariantKey(%q, %q) = %q, want %q", tc.thumb, tc.format, got, tc.want)
+		}
+		if got != "" && got == tc.thumb {
+			t.Errorf("VariantKey(%q, %q) overwrites the thumbnail", tc.thumb, tc.format)
+		}
+	}
+}
+
+// TestVariantKeyOfThumbFilename pins the variant of a real thumbnail name
+// (ThumbFilename in the original's partition directory): it keeps the
+// directory and the stem and differs only in the extension, for an
+// original of each common format.
+func TestVariantKeyOfThumbFilename(t *testing.T) {
+	for _, ext := range []string{"jpg", "png", "gif", "webp"} {
+		disk := "abc123def456ghi789jkl0." + ext
+		thumb := PartitionDirectory(disk) + ThumbFilename(42, 480, 320, 0, 0, "exact", ext)
+		got := VariantKey(thumb, "webp")
+		stem := strings.TrimSuffix(thumb, "."+ext)
+		if got == thumb || !strings.HasPrefix(got, stem+".") || !strings.HasSuffix(got, ".webp") || strings.Contains(strings.TrimPrefix(got, stem), "/") {
+			t.Errorf("%s: VariantKey(%q) = %q", disk, thumb, got)
+		}
+	}
+}