Trim compiler error output for better readability

Previously, compiler outputted whole executable in error context. This
caused long and hard to read error messages, especially when the
executable is a long category with many children. This commit improves
readability by trimming the error output.

Changes:

- Trim the error output (max characters: 1000).
- Improve indenting and newlines.

src/application/Parser/Executable/Validation/ExecutableErrorContextMessage.ts

@@ -18,18 +18,26 @@ export const createExecutableContextErrorMessage: ExecutableContextErrorMessageC
     message += `${ExecutableType[context.type]}: `;
   }
   message += errorMessage;
-  message += `\n${getErrorContextDetails(context)}`;
+  message += `\n\n${getErrorContextDetails(context)}`;
   return message;
 };
 
 function getErrorContextDetails(context: ExecutableErrorContext): string {
-  let output = `Self: ${printExecutable(context.self)}`;
+  let output = `Executable: ${formatExecutable(context.self)}`;
   if (context.parentCategory) {
-    output += `\nParent: ${printExecutable(context.parentCategory)}`;
+    output += `\n\nParent category: ${formatExecutable(context.parentCategory)}`;
   }
   return output;
 }
 
-function printExecutable(executable: ExecutableData): string {
+function formatExecutable(executable: ExecutableData): string {
-  return JSON.stringify(executable, undefined, 2);
+  if (!executable) {
+    return 'Executable data is missing.';
+  }
+  const maxLength = 1000;
+  let output = JSON.stringify(executable, undefined, 2);
+  if (output.length > maxLength) {
+    output = `${output.substring(0, maxLength)}\n... [Rest of the executable trimmed]`;
+  }
+  return output;
 }

tests/unit/application/Parser/Executable/Validation/ExecutableErrorContextMessage.spec.ts

@@ -0,0 +1,194 @@
+import { describe, it, expect } from 'vitest';
+import { createExecutableErrorContextStub } from '@tests/unit/shared/Stubs/ExecutableErrorContextStub';
+import { createExecutableContextErrorMessage } from '@/application/Parser/Executable/Validation/ExecutableErrorContextMessage';
+import type { ExecutableErrorContext } from '@/application/Parser/Executable/Validation/ExecutableErrorContext';
+import { ExecutableType } from '@/application/Parser/Executable/Validation/ExecutableType';
+import { CategoryDataStub } from '@tests/unit/shared/Stubs/CategoryDataStub';
+
+describe('ExecutableErrorContextMessage', () => {
+  describe('createExecutableContextErrorMessage', () => {
+    it('includes the specified error message', () => {
+      // arrange
+      const expectedErrorMessage = 'expected error message';
+      const context = new TestContext()
+        .withErrorMessage(expectedErrorMessage);
+      // act
+      const actualMessage = context.createExecutableContextErrorMessage();
+      // assert
+      expect(actualMessage).to.include(expectedErrorMessage);
+    });
+    it('includes the type of executable', () => {
+      // arrange
+      const executableType = ExecutableType.Category;
+      const expectedType = ExecutableType[executableType];
+      const errorContext: ExecutableErrorContext = {
+        type: executableType,
+        self: new CategoryDataStub(),
+      };
+      const context = new TestContext()
+        .withErrorContext(errorContext);
+      // act
+      const actualMessage = context.createExecutableContextErrorMessage();
+      // assert
+      expect(actualMessage).to.include(expectedType);
+    });
+    it('includes details of the self executable', () => {
+      // arrange
+      const expectedName = 'expected name';
+      const selfExecutable = new CategoryDataStub()
+        .withName(expectedName);
+      const errorContext: ExecutableErrorContext = {
+        type: ExecutableType.Category,
+        self: selfExecutable,
+      };
+      const context = new TestContext()
+        .withErrorContext(errorContext);
+      // act
+      const actualMessage = context.createExecutableContextErrorMessage();
+      // assert
+      expect(actualMessage).to.include(expectedName);
+    });
+    it('includes details of the parent category', () => {
+      // arrange
+      const expectedName = 'expected parent name';
+      const parentCategoryData = new CategoryDataStub()
+        .withName(expectedName);
+      const errorContext: ExecutableErrorContext = {
+        type: ExecutableType.Category,
+        self: new CategoryDataStub(),
+        parentCategory: parentCategoryData,
+      };
+      const context = new TestContext()
+        .withErrorContext(errorContext);
+      // act
+      const actualMessage = context.createExecutableContextErrorMessage();
+      // assert
+      expect(actualMessage).to.include(expectedName);
+    });
+    it('constructs the complete message format correctly', () => {
+      // arrange
+      const errorMessage = 'expected error message';
+      const expectedName = 'expected name';
+      const expectedFormat = new RegExp(`^${escapeRegExp(errorMessage)}\\s+Executable:\\s+{\\s+"name":\\s+"${escapeRegExp(expectedName)}"\\s+}`);
+      const errorContext: ExecutableErrorContext = {
+        self: {
+          name: expectedName,
+        } as unknown as ExecutableErrorContext['self'],
+      };
+      const context = new TestContext()
+        .withErrorContext(errorContext)
+        .withErrorMessage(errorMessage);
+      // act
+      const actualMessage = context.createExecutableContextErrorMessage();
+      // assert
+      expect(actualMessage).to.match(expectedFormat);
+    });
+    describe('output trimming', () => {
+      const totalLongTextDataCharacters = 5000;
+      const expectedTrimmedText = '[Rest of the executable trimmed]';
+      const longName = 'a'.repeat(totalLongTextDataCharacters);
+      const testScenarios: readonly {
+        readonly description: string;
+        readonly errorContext: ExecutableErrorContext;
+      } [] = [
+        {
+          description: 'long text from parent category data',
+          errorContext: {
+            type: ExecutableType.Category,
+            self: new CategoryDataStub(),
+            parentCategory: new CategoryDataStub().withName(longName),
+          },
+        },
+        {
+          description: 'long text from self executable data',
+          errorContext: {
+            type: ExecutableType.Category,
+            self: new CategoryDataStub().withName(longName),
+          },
+        },
+      ];
+      testScenarios.forEach(({
+        description, errorContext,
+      }) => {
+        it(description, () => {
+          const context = new TestContext()
+            .withErrorContext(errorContext);
+          // act
+          const actualMessage = context.createExecutableContextErrorMessage();
+          // assert
+          expect(actualMessage).to.include(expectedTrimmedText);
+          expect(actualMessage).to.have.length.lessThan(totalLongTextDataCharacters);
+        });
+      });
+    });
+    describe('missing data handling', () => {
+      it('generates a message when the executable type is undefined', () => {
+        // arrange
+        const errorContext: ExecutableErrorContext = {
+          type: undefined,
+          self: new CategoryDataStub(),
+        };
+        const context = new TestContext()
+          .withErrorContext(errorContext);
+        // act
+        const actualMessage = context.createExecutableContextErrorMessage();
+        // assert
+        expect(actualMessage).to.have.length.greaterThan(0);
+      });
+      it('generates a message when executable data is missing', () => {
+        // arrange
+        const errorContext: ExecutableErrorContext = {
+          type: undefined,
+          self: undefined as unknown as ExecutableErrorContext['self'],
+        };
+        const context = new TestContext()
+          .withErrorContext(errorContext);
+        // act
+        const actualMessage = context.createExecutableContextErrorMessage();
+        // assert
+        expect(actualMessage).to.have.length.greaterThan(0);
+      });
+      it('generates a message when parent category is missing', () => {
+        // arrange
+        const errorContext: ExecutableErrorContext = {
+          type: undefined,
+          self: new CategoryDataStub(),
+          parentCategory: undefined,
+        };
+        const context = new TestContext()
+          .withErrorContext(errorContext);
+        // act
+        const actualMessage = context.createExecutableContextErrorMessage();
+        // assert
+        expect(actualMessage).to.have.length.greaterThan(0);
+      });
+    });
+  });
+});
+
+class TestContext {
+  private errorMessage = `[${TestContext.name}] error message`;
+
+  private errorContext: ExecutableErrorContext = createExecutableErrorContextStub();
+
+  public withErrorMessage(errorMessage: string): this {
+    this.errorMessage = errorMessage;
+    return this;
+  }
+
+  public withErrorContext(context: ExecutableErrorContext): this {
+    this.errorContext = context;
+    return this;
+  }
+
+  public createExecutableContextErrorMessage() {
+    return createExecutableContextErrorMessage(
+      this.errorMessage,
+      this.errorContext,
+    );
+  }
+}
+
+function escapeRegExp(string: string): string {
+  return string.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');// $& means the whole matched string
+}