feat(assertions): support for parameters

packages/@aws-cdk/assertions/lib/private/parameters.ts

@@ -0,0 +1,30 @@
+import { filterLogicalId, formatFailure, matchSection } from './section';
+import { Template } from './template';
+
+export function findParameters(template: Template, logicalId: string, props: any = {}): { [key: string]: { [key: string]: any } } {
+  const section: { [key: string] : {} } = template.Parameters;
+  const result = matchSection(filterLogicalId(section, logicalId), props);
+
+  if (!result.match) {
+    return {};
+  }
+
+  return result.matches;
+}
+
+export function hasParameter(template: Template, logicalId: string, props: any): string | void {
+  const section: { [key: string] : {} } = template.Parameters;
+  const result = matchSection(filterLogicalId(section, logicalId), props);
+  if (result.match) {
+    return;
+  }
+
+  if (result.closestResult === undefined) {
+    return 'No parameters found in the template';
+  }
+
+  return [
+    `Template has ${result.analyzedCount} parameters, but none match as expected.`,
+    formatFailure(result.closestResult),
+  ].join('\n');
+}

packages/@aws-cdk/assertions/lib/private/template.ts

@@ -3,7 +3,8 @@
 export type Template = {
   Resources: { [logicalId: string]: Resource },
   Outputs: { [logicalId: string]: Output },
-  Mappings: { [logicalId: string]: Mapping }
+  Mappings: { [logicalId: string]: Mapping },
+  Parameters: { [logicalId: string]: Parameter }
 }
 
 export type Resource = {
@@ -13,4 +14,9 @@ export type Resource = {
 
 export type Output = { [key: string]: any };
 
-export type Mapping = { [key: string]: any };
+export type Mapping = { [key: string]: any };
+
+export type Parameter = {
+  Type: string;
+  [key: string]: any;
+}

packages/@aws-cdk/assertions/lib/template.ts

@@ -5,6 +5,7 @@ import { Match } from './match';
 import { Matcher } from './matcher';
 import { findMappings, hasMapping } from './private/mappings';
 import { findOutputs, hasOutput } from './private/outputs';
+import { findParameters, hasParameter } from './private/parameters';
 import { countResources, findResources, hasResource, hasResourceProperties } from './private/resources';
 import { Template as TemplateType } from './private/template';
 
@@ -108,6 +109,30 @@ export class Template {
     return findResources(this.template, type, props);
   }
 
+  /**
+   * Assert that a Parameter with the given properties exists in the CloudFormation template.
+   * By default, performs partial matching on the parameter, via the `Match.objectLike()`.
+   * To configure different behavior, use other matchers in the `Match` class.
+   * @param logicalId the name of the parameter. Provide `'*'` to match all parameters in the template.
+   * @param props the parameter as should be expected in the template.
+   */
+  public hasParameter(logicalId: string, props: any): void {
+    const matchError = hasParameter(this.template, logicalId, props);
+    if (matchError) {
+      throw new Error(matchError);
+    }
+  }
+
+  /**
+   * Get the set of matching Parameters that match the given properties in the CloudFormation template.
+   * @param logicalId the name of the parameter. Provide `'*'` to match all parameters in the template.
+   * @param props by default, matches all Parameters in the template.
+   * When a literal object is provided, performs a partial match via `Match.objectLike()`.
+   * Use the `Match` APIs to configure a different behaviour.   */
+  public findParameters(logicalId: string, props: any = {}): { [key: string]: { [key: string]: any } } {
+    return findParameters(this.template, logicalId, props);
+  }
+
   /**
    * Assert that an Output with the given properties exists in the CloudFormation template.
    * By default, performs partial matching on the resource, via the `Match.objectLike()`.

packages/@aws-cdk/assertions/test/template.test.ts

@@ -1,4 +1,4 @@
-import { App, CfnMapping, CfnOutput, CfnResource, NestedStack, Stack } from '@aws-cdk/core';
+import { App, CfnMapping, CfnOutput, CfnParameter, CfnResource, NestedStack, Stack } from '@aws-cdk/core';
 import { Construct } from 'constructs';
 import { Capture, Match, Template } from '../lib';
 
@@ -708,6 +708,156 @@ describe('Template', () => {
     });
   });
 
+  describe('findParameters', () => {
+    test('matching', () => {
+      const stack = new Stack();
+      new CfnParameter(stack, 'p1', {
+        type: 'String',
+        description: 'string parameter',
+      });
+      new CfnParameter(stack, 'p2', {
+        type: 'Number',
+        description: 'number parameter',
+      });
+
+      const inspect = Template.fromStack(stack);
+      const result = inspect.findParameters('*', { Type: 'String' });
+      expect(result).toEqual({
+        p1: {
+          Description: 'string parameter',
+          Type: 'String',
+        },
+      });
+    });
+
+    test('not matching', () => {
+      const stack = new Stack();
+      new CfnParameter(stack, 'p1', {
+        type: 'String',
+        description: 'string parameter',
+      });
+
+      const inspect = Template.fromStack(stack);
+      const result = inspect.findParameters('*', { Type: 'Number' });
+      expect(Object.keys(result).length).toEqual(0);
+    });
+
+    test('matching with specific parameter name', () => {
+      const stack = new Stack();
+      new CfnParameter(stack, 'p1', {
+        type: 'String',
+        description: 'string parameter',
+      });
+      new CfnParameter(stack, 'p2', {
+        type: 'Number',
+        description: 'number parameter',
+      });
+
+      const inspect = Template.fromStack(stack);
+      const result = inspect.findParameters('p1', { Type: 'String' });
+      expect(result).toEqual({
+        p1: {
+          Description: 'string parameter',
+          Type: 'String',
+        },
+      });
+    });
+
+    test('not matching specific parameter name', () => {
+      const stack = new Stack();
+      new CfnParameter(stack, 'p1', {
+        type: 'String',
+        description: 'string parameter',
+      });
+      new CfnParameter(stack, 'p2', {
+        type: 'Number',
+        description: 'number parameter',
+      });
+
+      const inspect = Template.fromStack(stack);
+      const result = inspect.findParameters('p3', { Type: 'String' });
+      expect(Object.keys(result).length).toEqual(0);
+    });
+  });
+
+  describe('hasParameter', () => {
+    test('matching', () => {
+      const stack = new Stack();
+      new CfnParameter(stack, 'p1', {
+        type: 'String',
+        description: 'string parameter',
+      });
+      new CfnParameter(stack, 'p2', {
+        type: 'Number',
+        description: 'number parameter',
+      });
+
+      const inspect = Template.fromStack(stack);
+      expect(() => inspect.findParameters('p3', { Type: 'String' })).not.toThrow();
+    });
+
+    test('not matching', (done) => {
+      const stack = new Stack();
+      new CfnParameter(stack, 'p1', {
+        type: 'String',
+        description: 'string parameter',
+      });
+      new CfnParameter(stack, 'p2', {
+        type: 'Number',
+        description: 'number parameter',
+      });
+
+      const inspect = Template.fromStack(stack);
+      expectToThrow(
+        () => inspect.hasParameter('*', { Type: 'CommaDelimitedList' }),
+        [
+          /2 parameters/,
+          /Expected CommaDelimitedList but received String/,
+        ],
+        done,
+      );
+      done();
+    });
+
+    test('matching specific parameter name', () => {
+      const stack = new Stack();
+      new CfnParameter(stack, 'p1', {
+        type: 'String',
+        description: 'string parameter',
+      });
+      new CfnParameter(stack, 'p2', {
+        type: 'Number',
+        description: 'number parameter',
+      });
+
+      const inspect = Template.fromStack(stack);
+      expect(() => inspect.findParameters('p1', { Type: 'String' })).not.toThrow();
+    });
+
+    test('not matching specific parameter name', (done) => {
+      const stack = new Stack();
+      new CfnParameter(stack, 'p1', {
+        type: 'String',
+        description: 'string parameter',
+      });
+      new CfnParameter(stack, 'p2', {
+        type: 'Number',
+        description: 'number parameter',
+      });
+
+      const inspect = Template.fromStack(stack);
+      expectToThrow(
+        () => inspect.hasParameter('p2', { Type: 'CommaDelimitedList' }),
+        [
+          /1 parameter/,
+          /Expected CommaDelimitedList but received Number/,
+        ],
+        done,
+      );
+      done();
+    });
+  });
+
   describe('findMappings', () => {
     test('matching', () => {
       const stack = new Stack();