e2e Go-native test runner

[cardil]

Rewrite the e2e-tests.sh script (https://github.com/knative/hack/blob/main/README.md#using-the-e2e-testssh-helper-script) into a Golang tool knative.dev/toolbox/presubmit.

Invent new Go-native extension interface, for example:

# will look for Go files with `e2e` build constraints, that register configuration
go run knative.dev/toolbox/e2e@latest --run-tests

An example configuration might look like:

//go:build e2e
package test

import (
  "fmt"
  "os"

  "github.com/bitfield/script"
  "knative.dev/toolbox/e2e/pkg/config"
  "knative.dev/toolbox/e2e/pkg/commands/knative"
  "knative.dev/toolbox/e2e/pkg/commands/wait"
)

var waitForKnative = true

init {
  config.Configure(config.Hooks{
    KnativeSetup: function(ctx config.Context) error {
      if err := knative.StartServingLatest(); err != nil {
        return err
      }
      if waitForKnative {
        return wait.UntilPodsRunning("knative-serving")
      }
      return nil
    },
    DefineFlags: function(fs *flag.FlagSet) {
      fs.BoolVar(&waitForKnative, "wait-for-knative", true, "wait for Knative install?")
    },
    Tests: []config.E2eSuite{{
      Name:  "Istio",
      Dir:   "./...",
      Flags: ["--istio"],
    }},
  })
}

[mgencur]

I have same question as #19 (comment) , it also applies to this issue.

[github-actions]

This issue is stale because it has been open for 90 days with no
activity. It will automatically close after 30 more days of
inactivity. Reopen the issue with /reopen. Mark the issue as
fresh by adding the comment /remove-lifecycle stale.

[cardil]

/reopen
/remove-lifecycle stale
/triage accepted

[knative-prow]

@cardil: Reopened this issue.

In response to this:

/reopen
/remove-lifecycle stale
/triage accepted

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.