Improve assertion error messages by adding mismatch descriptions

library/src/main/java/com/adevinta/android/barista/assertion/BaristaAssistiveTextAssertions.kt

@@ -26,14 +26,22 @@ object BaristaAssistiveTextAssertions {
   private fun matchAssistiveText(expectedAssistiveText: String): Matcher<View> {
     return object : TypeSafeMatcher<View>() {
       override fun describeTo(description: Description) {
-        description.appendText("with helper text: ").appendText(expectedAssistiveText)
+        description.appendText("with helper text: ").appendValue(expectedAssistiveText)
       }
 
       override fun matchesSafely(item: View): Boolean {
-        return when (item) {
-          is TextInputLayout -> expectedAssistiveText == item.helperText.toString()
+        return item.tryGetHelperText() == expectedAssistiveText
+      }
+
+      override fun describeMismatchSafely(item: View, mismatchDescription: Description) {
+        mismatchDescription.appendText("with helper text: ").appendValue(item.tryGetHelperText())
+      }
+
+      private fun View.tryGetHelperText(): String? {
+        return when (this) {
+          is TextInputLayout -> helperText?.toString()
           else -> {
-            throw UnsupportedOperationException("View of class ${item.javaClass.simpleName} not supported")
+            throw UnsupportedOperationException("View of class ${javaClass.simpleName} not supported")
           }
         }
       }

library/src/main/java/com/adevinta/android/barista/assertion/BaristaContentDescriptionAssertions.kt

@@ -37,18 +37,26 @@ object BaristaContentDescriptionAssertions {
       override fun matchesSafely(item: View): Boolean {
         return item.contentDescription.isNotBlank()
       }
+
+      override fun describeMismatchSafely(item: View, mismatchDescription: Description) {
+        mismatchDescription.appendText("with content description: ").appendValue(item.contentDescription.toString())
+      }
     }
   }
 
   private fun matchContentDescription(expectedContentDescription: String): Matcher<View> {
     return object : TypeSafeMatcher<View>() {
       override fun describeTo(description: Description) {
-        description.appendText("with content description: ").appendText(expectedContentDescription)
+        description.appendText("with content description: ").appendValue(expectedContentDescription)
       }
 
       override fun matchesSafely(item: View): Boolean {
         return item.contentDescription == expectedContentDescription
       }
+
+      override fun describeMismatchSafely(item: View, mismatchDescription: Description) {
+        mismatchDescription.appendText("with content description: ").appendValue(item.contentDescription.toString())
+      }
     }
   }
 }

library/src/main/java/com/adevinta/android/barista/assertion/BaristaErrorAssertions.kt

@@ -58,17 +58,15 @@ object BaristaErrorAssertions {
   private fun matchError(expectedError: String): Matcher<View> {
     return object : TypeSafeMatcher<View>() {
       override fun describeTo(description: Description) {
-        description.appendText("with error: ").appendText(expectedError)
+        description.appendText("with error: ").appendValue(expectedError)
+      }
+
+      override fun describeMismatchSafely(item: View, mismatchDescription: Description) {
+        mismatchDescription.appendText("with error: ").appendValue(item.tryGetErrorText())
       }
 
       override fun matchesSafely(item: View): Boolean {
-        return when (item) {
-          is TextView -> expectedError == item.error.toString()
-          is TextInputLayout -> expectedError == item.error.toString()
-          else -> {
-            throw UnsupportedOperationException("View of class ${item.javaClass.simpleName} not supported")
-          }
-        }
+        return expectedError == item.tryGetErrorText()
       }
     }
   }
@@ -79,14 +77,22 @@ object BaristaErrorAssertions {
         description.appendText("without error")
       }
 
+      override fun describeMismatchSafely(item: View, mismatchDescription: Description) {
+        mismatchDescription.appendText("with error: ").appendValue(item.tryGetErrorText())
+      }
+
       override fun matchesSafely(item: View): Boolean {
-        return when (item) {
-          is TextView -> item.error.isNullOrEmpty()
-          is TextInputLayout -> item.error.isNullOrEmpty()
-          else -> {
-            throw UnsupportedOperationException("View of class ${item.javaClass.simpleName} not supported")
-          }
-        }
+        return item.tryGetErrorText().isNullOrEmpty()
+      }
+    }
+  }
+
+  private fun View.tryGetErrorText(): String? {
+    return when (this) {
+      is TextView -> error?.toString()
+      is TextInputLayout -> error?.toString()
+      else -> {
+        throw UnsupportedOperationException("View of class ${javaClass.simpleName} not supported")
       }
     }
   }

library/src/main/java/com/adevinta/android/barista/assertion/BaristaHintAssertions.kt

@@ -31,23 +31,31 @@ object BaristaHintAssertions {
   private fun matchHint(expectedHint: String): Matcher<View> {
     return object : TypeSafeMatcher<View>() {
       override fun describeTo(description: Description) {
-        description.appendText("with hint: ").appendText(expectedHint)
+        description.appendText("with hint: ").appendValue(expectedHint)
       }
 
       override fun matchesSafely(item: View): Boolean {
-        return when (item) {
+        return item.tryGetHintText() == expectedHint
+      }
+
+      override fun describeMismatchSafely(item: View, mismatchDescription: Description) {
+        mismatchDescription.appendText("with hint: ").appendValue(item.tryGetHintText())
+      }
+
+      private fun View.tryGetHintText(): String? {
+        return when (this) {
           is TextInputLayout -> {
-            expectedHint == item.hint.toString()
+            hint?.toString()
           }
           is TextInputEditText -> {
-            val hint = ((item.parent as FrameLayout).parent as TextInputLayout).hint
-            expectedHint == hint
+            val hint = ((this.parent as FrameLayout).parent as TextInputLayout).hint
+            hint?.toString()
           }
           is EditText -> {
-            item.hint == expectedHint
+            hint?.toString()
           }
           else -> {
-            throw UnsupportedOperationException("View of class ${item.javaClass.simpleName} not supported")
+            throw UnsupportedOperationException("View of class ${javaClass.simpleName} not supported")
           }
         }
       }