Simple tests for db/migration (#421)

## Description

Some quick/shallow test for migration definition.

## Why is this needed

#371 introduced a migration where none of the names matched :D, the Id & FuncName was fixed in #383 but that one missed the file name. Why make humans do things they're bad at when instead we can make a computer do something its good at? So this is that :D.

## How Has This Been Tested?

Ran `go test` and it found the bad file name. I artificially changed an Id and the test caught the FuncName|Id mismatch.


## How are existing users impacted? What migration steps/scripts do we need?

N/A

## Checklist:

I have:

- [ ] updated the documentation and/or roadmap (if required)
- [x] added unit or e2e tests
- [ ] provided instructions on how to upgrade

db/migration/migration.go

@@ -1,16 +1,24 @@
 package migration
 
-import migrate "github.com/rubenv/sql-migrate"
+import (
+	migrate "github.com/rubenv/sql-migrate"
+)
+
+var migrations = []func() *migrate.Migration{
+	Get202009171251,
+	Get202010071530,
+	Get202010221010,
+	Get202012041103,
+	Get202012091055,
+	Get2020121691335,
+}
 
 func GetMigrations() *migrate.MemoryMigrationSource {
+	m := make([]*migrate.Migration, len(migrations))
+	for i := range migrations {
+		m[i] = migrations[i]()
+	}
 	return &migrate.MemoryMigrationSource{
-		Migrations: []*migrate.Migration{
-			Get202009171251(),
-			Get202010071530(),
-			Get202010221010(),
-			Get202012041103(),
-			Get202012091055(),
-			Get2020121691335(),
-		},
+		Migrations: m,
 	}
 }

db/migration/migration_test.go

@@ -0,0 +1,39 @@
+package migration
+
+import (
+	"path"
+	"reflect"
+	"runtime"
+	"strings"
+	"testing"
+
+	assert "github.com/stretchr/testify/require"
+)
+
+func TestMigrationFuncNamesMatchIDs(t *testing.T) {
+	timestamps := map[string]bool{}
+	for _, m := range migrations {
+		pc := reflect.ValueOf(m).Pointer()
+		fn := runtime.FuncForPC(pc)
+
+		file, _ := fn.FileLine(pc)
+		file = path.Base(file)
+		root := strings.TrimSuffix(file, path.Ext(file))
+
+		migration := m()
+		mid := strings.Split(migration.Id, "-")[0]
+
+		assert.Equal(t, root, migration.Id, "file root name (%s) and migration id (%s) do not match", root, migration.Id)
+
+		fnName := strings.Split(fn.Name(), "migration.")[1]
+		assert.Equal(t, fnName, "Get"+mid, "migration func name and id timestamp mismatch, func: %s, migration.Id: %s", fnName, mid)
+
+		assert.NotContains(t, timestamps, mid)
+	}
+
+}
+
+func TestGetMigrations(t *testing.T) {
+	m := GetMigrations()
+	assert.Len(t, m.Migrations, len(migrations))
+}