add test for issue option (#20)

__tests__/issue.test.ts

@@ -0,0 +1,44 @@
+import * as issue from '../src/issue'
+import {IssueOption} from '../src/interface'
+
+describe('getIssueOption', () => {
+  test('without assignee and label', () => {
+    process.env.INPUT_ISSUE_TITLE = 'npm audit found vulnerabilities'
+
+    const expected: IssueOption = {
+      title: 'npm audit found vulnerabilities',
+      body: 'hi',
+      assignees: [''],
+      labels: ['']
+    }
+    expect(issue.getIssueOption('hi')).toEqual(expected)
+  })
+
+  test('with 1 assignee and 1 label', () => {
+    process.env.INPUT_ISSUE_TITLE = 'npm audit found vulnerabilities'
+    process.env.INPUT_ISSUE_ASSIGNEES = 'alice'
+    process.env.INPUT_ISSUE_LABELS = 'foo'
+
+    const expected: IssueOption = {
+      title: 'npm audit found vulnerabilities',
+      body: 'hi',
+      assignees: ['alice'],
+      labels: ['foo']
+    }
+    expect(issue.getIssueOption('hi')).toEqual(expected)
+  })
+
+  test('with 2 assignees and 2 labels', () => {
+    process.env.INPUT_ISSUE_TITLE = 'npm audit found vulnerabilities'
+    process.env.INPUT_ISSUE_ASSIGNEES = 'alice,bob'
+    process.env.INPUT_ISSUE_LABELS = 'foo,bar'
+
+    const expected: IssueOption = {
+      title: 'npm audit found vulnerabilities',
+      body: 'hi',
+      assignees: ['alice', 'bob'],
+      labels: ['foo', 'bar']
+    }
+    expect(issue.getIssueOption('hi')).toEqual(expected)
+  })
+})