feat: migrate unit tests to Jest (#6353)

* config(jest): updated setup
* config(jest): update testMatch to include jsx files
* config(jest): add transformIgnorePatterns
* config(jest): update ignore files that do not work in jest yet
* config: add test:unit-jest to test script

* fix(jest): lint with eslint-plugin-jest

* refactor(jest): move unit test directory
* refactor(mocha): restore mocha tests that fail in jest

* docs(jest): update helpful scripts with test:unit-jest

test/unit/core/plugins/oas3/helpers.js

@@ -0,0 +1,67 @@
+import { fromJS } from "immutable"
+import { isOAS3, isSwagger2 } from "corePlugins/oas3/helpers"
+
+const isOAS3Shorthand = (version) => isOAS3(fromJS({
+  openapi: version
+}))
+
+const isSwagger2Shorthand = (version) => isSwagger2(fromJS({
+  swagger: version
+}))
+
+describe("isOAS3", function () {
+  it("should recognize valid OAS3 version values", function () {
+    expect(isOAS3Shorthand("3.0.0")).toEqual(true)
+    expect(isOAS3Shorthand("3.0.1")).toEqual(true)
+    expect(isOAS3Shorthand("3.0.11111")).toEqual(true)
+    expect(isOAS3Shorthand("3.0.0-rc0")).toEqual(true)
+  })
+
+  it("should fail for invalid OAS3 version values", function () {
+    expect(isOAS3Shorthand("3.0")).toEqual(false)
+    expect(isOAS3Shorthand("3.0.")).toEqual(false)
+    expect(isOAS3Shorthand("2.0")).toEqual(false)
+  })
+
+  it("should gracefully fail for non-string values", function () {
+    expect(isOAS3Shorthand(3.0)).toEqual(false)
+    expect(isOAS3Shorthand(3)).toEqual(false)
+    expect(isOAS3Shorthand({})).toEqual(false)
+    expect(isOAS3Shorthand(null)).toEqual(false)
+  })
+
+  it("should gracefully fail when `openapi` field is missing", function () {
+    expect(isOAS3(fromJS({
+      openApi: "3.0.0"
+    }))).toEqual(false)
+    expect(isOAS3Shorthand(null)).toEqual(false)
+  })
+})
+
+describe("isSwagger2", function () {
+  it("should recognize valid Swagger 2.0 version values", function () {
+    expect(isSwagger2Shorthand("2.0")).toEqual(true)
+    expect(isSwagger2Shorthand("2.0-rc0")).toEqual(true)
+  })
+
+  it("should fail for invalid Swagger 2.0 version values", function () {
+    expect(isSwagger2Shorthand("3.0")).toEqual(false)
+    expect(isSwagger2Shorthand("3.0.")).toEqual(false)
+    expect(isSwagger2Shorthand("2.1")).toEqual(false)
+    expect(isSwagger2Shorthand("1.2")).toEqual(false)
+    expect(isSwagger2Shorthand("2")).toEqual(false)
+  })
+
+  it("should gracefully fail for non-string values", function () {
+    expect(isSwagger2Shorthand(2.0)).toEqual(false)
+    expect(isSwagger2Shorthand(2)).toEqual(false)
+    expect(isSwagger2Shorthand({})).toEqual(false)
+    expect(isSwagger2Shorthand(null)).toEqual(false)
+  })
+
+  it("should gracefully fail when `swagger` field is missing", function () {
+    expect(isSwagger2(fromJS({
+      Swagger: "2.0"
+    }))).toEqual(false)
+  })
+})