Text equivalence between Text/Paragraph/Span/Style

Test: ./gradlew ui:ui-text:test

Bug: 143466124
Change-Id: I05fe385775c05b3142efbe6e7805ee935055aa9b

diff --git a/ui/ui-text/src/test/java/androidx/ui/text/TextSpanParagraphStyleTest.kt b/ui/ui-text/src/test/java/androidx/ui/text/TextSpanParagraphStyleTest.kt
index 1346145..05c2508 100644
--- a/ui/ui-text/src/test/java/androidx/ui/text/TextSpanParagraphStyleTest.kt
+++ b/ui/ui-text/src/test/java/androidx/ui/text/TextSpanParagraphStyleTest.kt

@@ -33,7 +33,9 @@
         val spanStyleParameters = constructorParams(SpanStyle::class)
         val textStyleParameters = constructorParams(TextStyle::class)
 
-        // assert that textStyleParameters contains all of spanStyleParameters
+        // for every SpanStyle parameter, expecting that parameter to be in TextStyle
+        // this guards that if a parameter is added to SpanStyle, it should be added
+        // to TextStyle
         assertThat(textStyleParameters).containsAtLeastElementsIn(spanStyleParameters)
     }
 
@@ -42,10 +44,27 @@
         val paragraphStyleParameters = constructorParams(ParagraphStyle::class)
         val textStyleParameters = constructorParams(TextStyle::class)
 
-        // assert that paragraphStyleParameters contains all of spanStyleParameters
+        // for every ParagraphStyle parameter, expecting that parameter to be in TextStyle
+        // this guards that if a parameter is added to ParagraphStyle, it should be added
+        // to TextStyle
         assertThat(textStyleParameters).containsAtLeastElementsIn(paragraphStyleParameters)
     }
 
+    @Test
+    fun textStyle_covered_by_ParagraphStyle_and_SpanStyle() {
+        val spanStyleParameters = constructorParams(SpanStyle::class)
+        val paragraphStyleParameters = constructorParams(ParagraphStyle::class)
+        val textStyleParameters = constructorParams(TextStyle::class)
+
+        // for every TextStyle parameter, expecting that parameter to be in either ParagraphStyle
+        // or SpanStyle
+        // this guards that if a parameter is added to TextStyle, it should be added
+        // to one of SpanStyle or ParagraphStyle
+        assertThat(spanStyleParameters + paragraphStyleParameters).containsAtLeastElementsIn(
+            textStyleParameters
+        )
+    }
+
     private fun <T : Any> constructorParams(clazz: KClass<T>): List<Parameter> {
         return clazz.primaryConstructor?.parameters?.map { Parameter(it) } ?: listOf()
     }