chore: adding unit tests

packages/sanity/flutter_sanity_portable_text/test/portable_text_test.dart

@@ -0,0 +1,89 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_sanity_portable_text/flutter_sanity_portable_text.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  testWidgets('PortableText can be created with required parameters',
+      (WidgetTester tester) async {
+    await tester.pumpWidget(const MaterialApp(
+      home: PortableText(blocks: []),
+    ));
+
+    expect(find.byType(PortableText), findsOneWidget);
+  });
+
+  testWidgets(
+      'PortableText uses primary scroller when usePrimaryScroller is true',
+      (WidgetTester tester) async {
+    await tester.pumpWidget(const MaterialApp(
+      home: PortableText(blocks: [], usePrimaryScroller: true),
+    ));
+
+    final listView = tester.widget<ListView>(find.byType(ListView));
+    expect(listView.primary, isTrue);
+  });
+
+  testWidgets('PortableText shrink-wraps the list view when shrinkwrap is true',
+      (WidgetTester tester) async {
+    await tester.pumpWidget(const MaterialApp(
+      home: PortableText(blocks: [], shrinkwrap: true),
+    ));
+
+    final listView = tester.widget<ListView>(find.byType(ListView));
+    expect(listView.shrinkWrap, isTrue);
+  });
+
+  testWidgets('PortableText correctly renders the blocks passed to it',
+      (WidgetTester tester) async {
+    final blocks = [
+      TextBlockItem(children: [
+        Span(text: 'Hello, '),
+        Span(text: 'World', marks: ['strong']),
+      ]),
+      TextBlockItem(children: [
+        Span(text: 'This is a '),
+        Span(text: 'test', marks: ['em']),
+      ]),
+    ];
+
+    await tester.pumpWidget(MaterialApp(
+      home: PortableText(blocks: blocks),
+    ));
+
+    expect(find.text('Hello, World', findRichText: true), findsOneWidget);
+    expect(find.textContaining('test', findRichText: true), findsOneWidget);
+
+    matchTextWithStyle(RichText widget, String text) {
+      return widget.text.visitChildren((span) {
+        if (span is TextSpan &&
+            span.text == text &&
+            span.style?.fontStyle == FontStyle.italic) return false;
+        return true;
+      });
+    }
+
+    expect(
+        find.byWidgetPredicate((widget) =>
+            widget is RichText && matchTextWithStyle(widget, 'test')),
+        findsOne);
+  });
+
+  testWidgets(
+      'PortableText shows an ErrorView when a builder for a block type is missing',
+      (WidgetTester tester) async {
+    final blocks = [const MissingPortableBlockItem()];
+
+    await tester.pumpWidget(MaterialApp(
+      home: PortableText(blocks: blocks),
+    ));
+
+    expect(find.byType(ErrorView), findsOneWidget);
+  });
+}
+
+final class MissingPortableBlockItem implements PortableBlockItem {
+  @override
+  final String blockType = 'missingType';
+
+  const MissingPortableBlockItem();
+}