🐛 Add attribute matcher

diff --git a/src/test/kotlin/net/pterodactylus/sone/test/Matchers.kt b/src/test/kotlin/net/pterodactylus/sone/test/Matchers.kt
index 644f192..d941c01 100644 (file)
--- a/src/test/kotlin/net/pterodactylus/sone/test/Matchers.kt
+++ b/src/test/kotlin/net/pterodactylus/sone/test/Matchers.kt
@@ -65,3 +65,58 @@ fun isIdentity(id: String, nickname: String, requestUri: String, contexts: Match
                                .addAttribute("contexts", Identity::getContexts, contexts)
                                .addAttribute("properties", Identity::getProperties, properties)
 
                                .addAttribute("contexts", Identity::getContexts, contexts)
                                .addAttribute("properties", Identity::getProperties, properties)
 

+/**
+ * [TypeSafeDiagnosingMatcher] implementation that aims to cut down boilerplate on verifying the attributes
+ * of typical container objects.
+ */
+class AttributeMatcher<T>(private val objectName: String) : TypeSafeDiagnosingMatcher<T>() {
+
+       private data class AttributeToMatch<T, V>(
+                       val name: String,
+                       val getter: (T) -> V,
+                       val matcher: Matcher<out V>
+       )
+
+       private val attributesToMatch = mutableListOf<AttributeToMatch<T, *>>()
+
+       /**
+        * Adds an attribute to check for equality, returning `this`.
+        */
+       fun <V> addAttribute(name: String, expected: V, getter: (T) -> V): AttributeMatcher<T> = apply {
+               attributesToMatch.add(AttributeToMatch(name, getter, describedAs("$name %0", equalTo(expected), expected)))
+       }
+
+       /**
+        * Adds an attribute to check with the given [hamcrest matcher][Matcher].
+        */
+       fun <V> addAttribute(name: String, getter: (T) -> V, matcher: Matcher<out V>) = apply {
+               attributesToMatch.add(AttributeToMatch(name, getter, matcher))
+       }
+
+       override fun describeTo(description: Description) {
+               attributesToMatch.forEachIndexed { index, attributeToMatch ->
+                       if (index == 0) {
+                               description.appendText("$objectName with ")
+                       } else {
+                               description.appendText(", ")
+                       }
+                       attributeToMatch.matcher.describeTo(description)
+               }
+       }
+
+       override fun matchesSafely(item: T, mismatchDescription: Description): Boolean =
+                       attributesToMatch.fold(true) { matches, attributeToMatch ->
+                               if (!matches) {
+                                       false
+                               } else {
+                                       if (!attributeToMatch.matcher.matches(attributeToMatch.getter(item))) {
+                                               mismatchDescription.appendText("but ${attributeToMatch.name} ")
+                                               attributeToMatch.matcher.describeMismatch(attributeToMatch.getter(item), mismatchDescription)
+                                               false
+                                       } else {
+                                               true
+                                       }
+                               }
+                       }
+
+}