Build/Test Tools: Expand unit tests for theme.json.

This changeset adds unit test coverage for the following features:

- Gradients
- `filter` (Duotones)
- `blockGap`
- `shadow`
- `useRootPaddingAwareAlignments`
- `appearanceTools`

Props gunterer, johnregan3, audrasjb, mukesh27.
Fixes #56611.


git-svn-id: https://develop.svn.wordpress.org/trunk@54443 602fd350-edb4-49c9-b593-d223f7449a82

tests/phpunit/data/themedir1/block-theme/theme.json

@@ -22,6 +22,13 @@
 					"slug": "custom-gradient"
 				}
 			],
+			"duotone": [
+				{
+					"colors": [ "#333333", "#aaaaaa" ],
+					"slug": "custom-duotone",
+					"name": "Custom Duotone"
+				}
+			],
 			"custom": false,
 			"customGradient": false
 		},
@@ -38,7 +45,8 @@
 		},
 		"spacing": {
 			"units": ["rem"],
-			"customPadding": true
+			"customPadding": true,
+			"blockGap": true
 		},
 		"blocks": {
 			"core/paragraph": {
@@ -54,6 +62,45 @@
 			}
 		}
 	},
+	"styles" : {
+		"blocks" :{
+			"core/post-featured-image": {
+				"shadow": "10px 10px 5px 0px rgba(0,0,0,0.66)",
+				"filter": {
+					"duotone": "var(--wp--preset--duotone--custom-duotone)"
+				}
+			}
+		},
+		"elements": {
+			"button": {
+				"shadow": "10px 10px 5px 0px rgba(0,0,0,0.66)"
+			},
+			"link": {
+				"typography": {
+					"textDecoration": "none"
+				},
+				"border": {
+					"bottom": {
+						"width": "2px",
+						"color": "currentColor",
+						"style": "solid"
+					}
+				},
+				":hover": {
+					"typography": {
+						"textDecoration": "none"
+					},
+					"border": {
+						"bottom": {
+							"width": "2px",
+							"color": "#000",
+							"style": "dotted"
+						}
+					}
+				}
+			}
+		}
+	},
 	"customTemplates": [
 		{
 			"name": "page-home",
@@ -72,4 +119,4 @@
 			"area": "header"
 		}
 	]
-}
+}