integration: add single-cluster integration tests (#2516)

* integration: add single-cluster integration tests

* remove kind load

integration/forms/forms.go

@@ -0,0 +1,93 @@
+// Package forms has helper functions for working with HTML forms.
+package forms
+
+import (
+	"context"
+	"io"
+	"net/http"
+	"net/url"
+	"strings"
+
+	"golang.org/x/net/html"
+)
+
+// A Form represents an HTML form.
+type Form struct {
+	Action string
+	Method string
+	Inputs map[string]string
+}
+
+// Parse parses all the forms in an HTML document.
+func Parse(r io.Reader) []Form {
+	root, err := html.Parse(r)
+	if err != nil {
+		return nil
+	}
+
+	var forms []Form
+	var currentForm *Form
+	var visit func(*html.Node)
+	visit = func(node *html.Node) {
+		if node.Type == html.ElementNode && node.Data == "form" {
+			currentForm = &Form{Action: "", Method: "GET", Inputs: make(map[string]string)}
+			for _, attr := range node.Attr {
+				switch attr.Key {
+				case "action":
+					currentForm.Action = attr.Val
+				case "method":
+					currentForm.Method = strings.ToUpper(attr.Val)
+				}
+			}
+		}
+
+		if currentForm != nil && node.Type == html.ElementNode && node.Data == "input" {
+			var name, value string
+			for _, attr := range node.Attr {
+				switch attr.Key {
+				case "name":
+					name = attr.Val
+				case "value":
+					value = attr.Val
+				}
+			}
+			if name != "" {
+				currentForm.Inputs[name] = value
+			}
+		}
+
+		for c := node.FirstChild; c != nil; c = c.NextSibling {
+			visit(c)
+		}
+		if node.Type == html.ElementNode && node.Data == "form" {
+			if currentForm != nil {
+				forms = append(forms, *currentForm)
+			}
+			currentForm = nil
+		}
+	}
+	visit(root)
+	return forms
+}
+
+// NewRequestWithContext creates a new request from the form details.
+func (f *Form) NewRequestWithContext(ctx context.Context, baseURL *url.URL) (*http.Request, error) {
+	actionURL, err := url.Parse(f.Action)
+	if err != nil {
+		return nil, err
+	}
+	actionURL = baseURL.ResolveReference(actionURL)
+
+	vs := make(url.Values)
+	for k, v := range f.Inputs {
+		vs.Set(k, v)
+	}
+
+	req, err := http.NewRequestWithContext(ctx, f.Method, actionURL.String(), strings.NewReader(vs.Encode()))
+	if err != nil {
+		return nil, err
+	}
+	// TODO: handle multipart forms
+	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+	return req, nil
+}