go: Fix build: add go.mod, proper imports, and make test pass

go/go.mod

@@ -0,0 +1,3 @@
+module github.com/guardian/coding-exercise-project/go
+
+go 1.21

go/main.go

@@ -1,7 +1,11 @@
 package main
 
-import "./src"
+import (
+	"fmt"
+
+	"github.com/guardian/coding-exercise-project/go/src"
+)
 
 func main() {
-  println(pairing.SayHello())
+	fmt.Println(pairing.SayHello())
 }

go/script/test

@@ -1,9 +1,7 @@
 #!/usr/bin/env bash
 
-set -e
+set -euo pipefail
 
-pushd src
+cd "$(dirname "${BASH_SOURCE[0]}")/.."
 
-go test
-
-popd
+go test ./...

go/src/pairing.go

@@ -1,5 +1,5 @@
 package pairing
 
 func SayHello() string {
-  return "hi"
+	return "hello"
 }

go/src/pairing_test.go

@@ -2,12 +2,8 @@ package pairing
 
 import "testing"
 
-func TestNothing(t *testing.T) {
-  t.Skip("no implemented")
-}
-
 func TestSimpleString(t *testing.T) {
-  if SayHello() != "hello" {
-    t.Error("couldn't get hello message")
-  }
+	if SayHello() != "hello" {
+		t.Error("couldn't get hello message")
+	}
 }