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Validating Color Resource Binding Integration in Butterknife

This test suite validates the color binding functionality in Butterknife, focusing on both integer color values and ColorStateList resources. The tests ensure proper binding and unbinding of color resources in Android applications.

Test Coverage Overview

The test suite covers two primary color binding scenarios in Butterknife:

Integer color resource binding and validation
ColorStateList resource binding and comparison
Proper resource unbinding behavior
Integration with Android’s resource system

Implementation Analysis

The testing approach utilizes JUnit4 with Android Instrumentation testing framework. It implements two distinct test cases using separate target classes to isolate color binding behaviors.

Uses ButterKnife.bind() for resource injection
Leverages Truth assertion library for validation
Implements proper cleanup through unbinder verification

Technical Details

Testing infrastructure includes:

AndroidX Test framework
JUnit4 test runner
Google Truth assertion library
Android Instrumentation Registry for context access
Custom ViewTree utility for view hierarchy simulation

Best Practices Demonstrated

The test suite exemplifies several testing best practices:

Isolated test cases for different resource types
Proper resource cleanup after tests
Clear separation of test targets and assertions
Effective use of annotations for resource binding
Comprehensive verification of both binding and unbinding states

jakewharton/butterknife

butterknife-integration-test/src/androidTest/java/com/example/butterknife/functional/BindColorTest.java

            
package com.example.butterknife.functional;

import android.content.Context;
import android.content.res.ColorStateList;
import android.view.View;
import androidx.test.InstrumentationRegistry;
import butterknife.BindColor;
import butterknife.ButterKnife;
import butterknife.Unbinder;
import com.example.butterknife.test.R;
import org.junit.Test;

import static com.google.common.truth.Truth.assertThat;

public final class BindColorTest {
  private final Context context = InstrumentationRegistry.getContext();
  private final View tree = ViewTree.create(1);

  static class IntTarget {
    @BindColor(R.color.red) int actual;
  }

  @Test public void asInt() {
    IntTarget target = new IntTarget();
    int expected = context.getResources().getColor(R.color.red);

    Unbinder unbinder = ButterKnife.bind(target, tree);
    assertThat(target.actual).isEqualTo(expected);

    unbinder.unbind();
    assertThat(target.actual).isEqualTo(expected);
  }

  static class ColorStateListTarget {
    @BindColor(R.color.colors) ColorStateList actual;
  }

  @Test public void asColorStateList() {
    ColorStateListTarget target = new ColorStateListTarget();
    ColorStateList expected = context.getResources().getColorStateList(R.color.colors);

    Unbinder unbinder = ButterKnife.bind(target, tree);
    assertThat(target.actual.toString()).isEqualTo(expected.toString());

    unbinder.unbind();
    assertThat(target.actual.toString()).isEqualTo(expected.toString());
  }
}