Back to Repositories

Validating Dialog View Binding Implementation in ButterKnife

This test suite validates the functionality of Butterknife’s view binding capabilities in Android Dialog extensions. It ensures proper generation of binding code for both resource and view bindings, verifying the framework’s ability to handle Dialog-specific view hierarchies.

Test Coverage Overview

The test suite provides comprehensive coverage of Butterknife’s Dialog extension functionality:

Resource binding validation for boolean resources
View binding verification in Dialog contexts
Generated code structure and syntax verification
Proper implementation of Unbinder interface

Implementation Analysis

The testing approach utilizes JUnit for structured test cases and Google’s compile-testing framework for code generation validation. It employs a combination of source code compilation and generated code comparison to verify the correct implementation of view bindings in Dialog extensions.

Source code compilation verification
Generated binding class structure validation
Annotation processing verification

Technical Details

Testing infrastructure includes:

ButterKnifeProcessor for annotation processing
JavaFileObjects for source code representation
Google Truth assertions for compile-time validation
Custom compiler options for processing verification

Best Practices Demonstrated

The test suite exemplifies several testing best practices:

Isolated test cases for different binding scenarios
Comprehensive verification of generated code
Clear separation of resource and view binding tests
Proper handling of compilation warnings and errors

jakewharton/butterknife

butterknife-runtime/src/test/java/butterknife/ExtendDialogTest.java

            
package butterknife;

import butterknife.compiler.ButterKnifeProcessor;
import com.google.testing.compile.JavaFileObjects;
import javax.tools.JavaFileObject;
import org.junit.Test;

import static com.google.common.truth.Truth.assertAbout;
import static com.google.testing.compile.JavaSourceSubjectFactory.javaSource;

public class ExtendDialogTest {
  @Test public void onlyResources() {
    JavaFileObject source = JavaFileObjects.forSourceString("test.Test", ""
        + "package test;"
        + "import android.app.Dialog;"
        + "import android.content.Context;"
        + "import butterknife.BindBool;"
        + "public class Test extends Dialog {"
        + "  Test(Context context) {"
        + "    super(context);"
        + "  }"
        + "  @BindBool(1) boolean one;"
        + "}"
    );

    JavaFileObject bindingSource = JavaFileObjects.forSourceString("test/Test_ViewBinding", ""
        + "// Generated code from Butter Knife. Do not modify!\n"
        + "package test;\n"
        + "import android.content.Context;\n"
        + "import android.content.res.Resources;\n"
        + "import android.view.View;\n"
        + "import androidx.annotation.CallSuper;\n"
        + "import androidx.annotation.UiThread;\n"
        + "import butterknife.Unbinder;\n"
        + "import java.lang.Deprecated;\n"
        + "import java.lang.Override;\n"
        + "import java.lang.SuppressWarnings;\n"
        + "public class Test_ViewBinding implements Unbinder {\n"
        + "  @UiThread\n"
        + "  public Test_ViewBinding(Test target) {\n"
        + "    this(target, target.getContext());\n"
        + "  }\n"
        + "  /**\n"
        + "   * @deprecated Use {@link #Test_ViewBinding(Test, Context)} for direct creation.\n"
        + "   *     Only present for runtime invocation through {@code ButterKnife.bind()}.\n"
        + "   */\n"
        + "  @Deprecated\n"
        + "  @UiThread\n"
        + "  public Test_ViewBinding(Test target, View source) {\n"
        + "    this(target, source.getContext());\n"
        + "  }\n"
        + "  @UiThread\n"
        + "  @SuppressWarnings(\"ResourceType\")\n"
        + "  public Test_ViewBinding(Test target, Context context) {\n"
        + "    Resources res = context.getResources();\n"
        + "    target.one = res.getBoolean(1);\n"
        + "  }\n"
        + "  @Override\n"
        + "  @CallSuper\n"
        + "  public void unbind() {\n"
        + "  }\n"
        + "}"
    );

    assertAbout(javaSource()).that(source)
        .withCompilerOptions("-Xlint:-processing")
        .processedWith(new ButterKnifeProcessor())
        .compilesWithoutWarnings()
        .and()
        .generatesSources(bindingSource);
  }

  @Test public void views() {
    JavaFileObject source = JavaFileObjects.forSourceString("test.Test", ""
        + "package test;"
        + "import android.app.Dialog;"
        + "import android.content.Context;"
        + "import android.view.View;"
        + "import butterknife.BindView;"
        + "public class Test extends Dialog {"
        + "  Test(Context context) {"
        + "    super(context);"
        + "  }"
        + "  @BindView(1) View one;"
        + "}"
    );

    JavaFileObject bindingSource = JavaFileObjects.forSourceString("test/Test_ViewBinding", ""
        + "package test;\n"
        + "import android.view.View;\n"
        + "import androidx.annotation.CallSuper;\n"
        + "import androidx.annotation.UiThread;\n"
        + "import butterknife.Unbinder;\n"
        + "import butterknife.internal.Utils;\n"
        + "import java.lang.IllegalStateException;\n"
        + "import java.lang.Override;\n"
        + "public class Test_ViewBinding implements Unbinder {\n"
        + "  private Test target;\n"
        + "  @UiThread\n"
        + "  public Test_ViewBinding(Test target) {\n"
        + "    this(target, target.getWindow().getDecorView());\n"
        + "  }\n"
        + "  @UiThread\n"
        + "  public Test_ViewBinding(Test target, View source) {\n"
        + "    this.target = target;\n"
        + "    target.one = Utils.findRequiredView(source, 1, \"field 'one'\");\n"
        + "  }\n"
        + "  @Override\n"
        + "  @CallSuper\n"
        + "  public void unbind() {\n"
        + "    Test target = this.target;\n"
        + "    if (target == null) throw new IllegalStateException(\"Bindings already cleared.\");\n"
        + "    this.target = null;\n"
        + "    target.one = null;\n"
        + "  }\n"
        + "}"
    );

    assertAbout(javaSource()).that(source)
        .withCompilerOptions("-Xlint:-processing")
        .processedWith(new ButterKnifeProcessor())
        .compilesWithoutWarnings()
        .and()
        .generatesSources(bindingSource);
  }
}