From f3990f950277c2f61e0e1811b4b8a81fc0219da4 Mon Sep 17 00:00:00 2001
From: Will Hawkins <hawkinsw@obs.cr>
Date: Wed, 13 Dec 2023 19:56:03 -0500
Subject: [Feature] Support for testing upload/download in parallel

Use the `--rpm.parallel` to test in parallel mode. The default testing
mode is serial.

Signed-off-by: Will Hawkins <hawkinsw@obs.cr>
---
 executor/executor.go      | 53 ++++++++++++++++++++++++++++++++++++++++++++
 executor/executor_test.go | 56 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 109 insertions(+)
 create mode 100644 executor/executor.go
 create mode 100644 executor/executor_test.go

(limited to 'executor')

diff --git a/executor/executor.go b/executor/executor.go
new file mode 100644
index 0000000..22c1235
--- /dev/null
+++ b/executor/executor.go
@@ -0,0 +1,53 @@
+package executor
+
+import (
+	"sync"
+)
+
+type ExecutionMethod int
+
+const (
+	Parallel ExecutionMethod = iota
+	Serial
+)
+
+type ExecutionUnit func()
+
+func (ep ExecutionMethod) ToString() string {
+	switch ep {
+	case Parallel:
+		return "Parallel"
+	case Serial:
+		return "Serial"
+	}
+	return "Unrecognized execution method"
+}
+
+func Execute(executionMethod ExecutionMethod, executionUnits []ExecutionUnit) *sync.WaitGroup {
+	waiter := &sync.WaitGroup{}
+
+	// Make sure that we Add to the wait group all the execution units
+	// before starting to run any -- there is a potential race condition
+	// otherwise.
+	(*waiter).Add(len(executionUnits))
+
+	for _, executionUnit := range executionUnits {
+		// Stupid capture in Go! Argh.
+		executionUnit := executionUnit
+
+		invoker := func() {
+			executionUnit()
+			(*waiter).Done()
+		}
+		switch executionMethod {
+		case Parallel:
+			go invoker()
+		case Serial:
+			invoker()
+		default:
+			panic("Invalid execution method value given.")
+		}
+	}
+
+	return waiter
+}
diff --git a/executor/executor_test.go b/executor/executor_test.go
new file mode 100644
index 0000000..9c3af7e
--- /dev/null
+++ b/executor/executor_test.go
@@ -0,0 +1,56 @@
+package executor_test
+
+import (
+	"testing"
+	"time"
+
+	"github.com/network-quality/goresponsiveness/executor"
+)
+
+var countToFive = func() {
+	time.Sleep(5 * time.Second)
+}
+
+var countToThree = func() {
+	time.Sleep(3 * time.Second)
+}
+
+var executionUnits = []executor.ExecutionUnit{countToFive, countToThree}
+
+func TestSerial(t *testing.T) {
+	then := time.Now()
+	waiter := executor.Execute(executor.Serial, executionUnits)
+	waiter.Wait()
+	when := time.Now()
+
+	if when.Sub(then) < 7*time.Second {
+		t.Fatalf("Execution did not happen serially -- the wait was too short: %v", when.Sub(then).Seconds())
+	}
+}
+
+func TestParallel(t *testing.T) {
+	then := time.Now()
+	waiter := executor.Execute(executor.Parallel, executionUnits)
+	waiter.Wait()
+	when := time.Now()
+
+	if when.Sub(then) > 6*time.Second {
+		t.Fatalf("Execution did not happen in parallel -- the wait was too long: %v", when.Sub(then).Seconds())
+	}
+}
+
+func TestExecutionMethodParallelToString(t *testing.T) {
+	executionMethod := executor.Parallel
+
+	if executionMethod.ToString() != "Parallel" {
+		t.Fatalf("Incorrect result from ExecutionMethod.ToString; expected Parallel but got %v", executionMethod.ToString())
+	}
+}
+
+func TestExecutionMethodSerialToString(t *testing.T) {
+	executionMethod := executor.Serial
+
+	if executionMethod.ToString() != "Serial" {
+		t.Fatalf("Incorrect result from ExecutionMethod.ToString; expected Serial but got %v", executionMethod.ToString())
+	}
+}
-- 
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