Fix oppia#1884: Thoroughly test TextInputCaseSensitiveEqualsRuleClass…

…ifierProvider (oppia#1961)

* Added text cases for TextInputCaseSensitiveEqualsRuleClassifierProvider

* Resolved failed lint tests due to naming convention, file end line rule and wrong file name

* Modified TextInputCaseSensitiveEqualsRuleClassifierProviderTest

- Removed TODO statements
- Replaced Truth import with Truth.assertThat
- Replaced STRING_VALUE with STRING_VALUE_RANDOM
- Removed ktlint-disabling comments

* Removed TODO from TextInputCaseSensitiveEqualsRuleClassifierProvider class

domain/src/main/java/org/oppia/android/domain/classify/rules/textinput/TextInputCaseSensitiveEqualsRuleClassifierProvider.kt

@@ -25,7 +25,6 @@ internal class TextInputCaseSensitiveEqualsRuleClassifierProvider @Inject constr
     )
   }
 
-  // TODO(#210): Add tests for this classifier.
   override fun matches(answer: String, input: String): Boolean {
     return answer.normalizeWhitespace() == input.normalizeWhitespace()
   }

domain/src/test/java/org/oppia/android/domain/classify/rules/textinput/TextInputCaseSensitiveEqualsRuleClassifierProviderTest.kt

@@ -0,0 +1,137 @@
+package org.oppia.android.domain.classify.rules.textinput
+
+import android.app.Application
+import androidx.test.core.app.ApplicationProvider
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import com.google.common.truth.Truth.assertThat
+import dagger.BindsInstance
+import dagger.Component
+import org.junit.Before
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.oppia.android.app.model.InteractionObject
+import org.robolectric.annotation.Config
+import org.robolectric.annotation.LooperMode
+import javax.inject.Inject
+import javax.inject.Singleton
+import kotlin.reflect.KClass
+import kotlin.reflect.full.cast
+import kotlin.test.fail
+
+/** Tests for [TextInputCaseSensitiveEqualsRuleClassifierProvider]. */
+@RunWith(AndroidJUnit4::class)
+@LooperMode(LooperMode.Mode.PAUSED)
+@Config(manifest = Config.NONE)
+class TextInputCaseSensitiveEqualsRuleClassifierProviderTest {
+  private val STRING_VALUE_TEST_UPPERCASE = createString(value = "TEST")
+  private val STRING_VALUE_TEST_LOWERCASE = createString(value = "test")
+  private val STRING_VALUE_RANDOM = createString(value = "random")
+
+  @Inject
+  internal lateinit var textInputCaseSensitiveEqualsRuleClassifierProvider:
+    TextInputCaseSensitiveEqualsRuleClassifierProvider
+
+  private val inputCaseSensitiveEqualsRuleClassifier by lazy {
+    textInputCaseSensitiveEqualsRuleClassifierProvider.createRuleClassifier()
+  }
+
+  @Before
+  fun setUp() {
+    setUpTestApplicationComponent()
+  }
+
+  @Test
+  fun testUppercaseStringAnswer_uppercaseStringInput_sameExactString_bothValuesMatch() {
+    val inputs = mapOf("x" to STRING_VALUE_TEST_UPPERCASE)
+
+    val matches =
+      inputCaseSensitiveEqualsRuleClassifier.matches(
+        answer = STRING_VALUE_TEST_UPPERCASE,
+        inputs = inputs
+      )
+
+    assertThat(matches).isTrue()
+  }
+
+  @Test
+  fun testUppercaseStringAnswer_lowercaseStringInput_sameExactString_bothValuesDoNotMatch() {
+    val inputs = mapOf("x" to STRING_VALUE_TEST_LOWERCASE)
+
+    val matches =
+      inputCaseSensitiveEqualsRuleClassifier.matches(
+        answer = STRING_VALUE_TEST_UPPERCASE,
+        inputs = inputs
+      )
+
+    assertThat(matches).isFalse()
+  }
+
+  @Test
+  fun testUppercaseStringAnswer_stringRandomInput_differentString_bothValuesDoNotMatch() {
+    val inputs = mapOf("x" to STRING_VALUE_RANDOM)
+
+    val matches =
+      inputCaseSensitiveEqualsRuleClassifier.matches(
+        answer = STRING_VALUE_TEST_UPPERCASE,
+        inputs = inputs
+      )
+
+    assertThat(matches).isFalse()
+  }
+
+  @Test
+  fun testStringAnswer_missingInput_throwsException() {
+    val inputs = mapOf("y" to STRING_VALUE_TEST_LOWERCASE)
+
+    val exception = assertThrows(IllegalStateException::class) {
+      inputCaseSensitiveEqualsRuleClassifier.matches(
+        answer = STRING_VALUE_TEST_LOWERCASE,
+        inputs = inputs
+      )
+    }
+
+    assertThat(exception)
+      .hasMessageThat()
+      .contains("Expected classifier inputs to contain parameter with name 'x'")
+  }
+
+  private fun setUpTestApplicationComponent() {
+    DaggerTextInputCaseSensitiveEqualsRuleClassifierProviderTest_TestApplicationComponent.builder()
+      .setApplication(ApplicationProvider.getApplicationContext())
+      .build()
+      .inject(this)
+  }
+
+  private fun createString(value: String): InteractionObject {
+    return InteractionObject.newBuilder().setNormalizedString(value).build()
+  }
+
+  // TODO(#89): Move to a common test library.
+  private fun <T : Throwable> assertThrows(type: KClass<T>, operation: () -> Unit): T {
+    try {
+      operation()
+      fail("Expected to encounter exception of $type")
+    } catch (t: Throwable) {
+      if (type.isInstance(t)) {
+        return type.cast(t)
+      }
+      // Unexpected exception; throw it.
+      throw t
+    }
+  }
+
+  // TODO(#89): Move this to a common test application component.
+  @Singleton
+  @Component(modules = [])
+  interface TestApplicationComponent {
+    @Component.Builder
+    interface Builder {
+      @BindsInstance
+      fun setApplication(application: Application): Builder
+
+      fun build(): TestApplicationComponent
+    }
+
+    fun inject(test: TextInputCaseSensitiveEqualsRuleClassifierProviderTest)
+  }
+}