lib/structs: factor reflection based structure manipulation into a library

lib/structs/structs_test.go

@@ -0,0 +1,112 @@
+package structs
+
+import (
+	"fmt"
+	"net/http"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+// returns the "%p" representation of the thing passed in
+func ptr(p interface{}) string {
+	return fmt.Sprintf("%p", p)
+}
+
+func TestSetDefaults(t *testing.T) {
+	old := http.DefaultTransport.(*http.Transport)
+	newT := new(http.Transport)
+	SetDefaults(newT, old)
+	// Can't use assert.Equal or reflect.DeepEqual for this as it has functions in
+	// Check functions by comparing the "%p" representations of them
+	assert.Equal(t, ptr(old.Proxy), ptr(newT.Proxy), "when checking .Proxy")
+	assert.Equal(t, ptr(old.DialContext), ptr(newT.DialContext), "when checking .DialContext")
+	// Check the other public fields
+	assert.Equal(t, ptr(old.Dial), ptr(newT.Dial), "when checking .Dial")
+	assert.Equal(t, ptr(old.DialTLS), ptr(newT.DialTLS), "when checking .DialTLS")
+	assert.Equal(t, old.TLSClientConfig, newT.TLSClientConfig, "when checking .TLSClientConfig")
+	assert.Equal(t, old.TLSHandshakeTimeout, newT.TLSHandshakeTimeout, "when checking .TLSHandshakeTimeout")
+	assert.Equal(t, old.DisableKeepAlives, newT.DisableKeepAlives, "when checking .DisableKeepAlives")
+	assert.Equal(t, old.DisableCompression, newT.DisableCompression, "when checking .DisableCompression")
+	assert.Equal(t, old.MaxIdleConns, newT.MaxIdleConns, "when checking .MaxIdleConns")
+	assert.Equal(t, old.MaxIdleConnsPerHost, newT.MaxIdleConnsPerHost, "when checking .MaxIdleConnsPerHost")
+	assert.Equal(t, old.IdleConnTimeout, newT.IdleConnTimeout, "when checking .IdleConnTimeout")
+	assert.Equal(t, old.ResponseHeaderTimeout, newT.ResponseHeaderTimeout, "when checking .ResponseHeaderTimeout")
+	assert.Equal(t, old.ExpectContinueTimeout, newT.ExpectContinueTimeout, "when checking .ExpectContinueTimeout")
+	assert.Equal(t, old.TLSNextProto, newT.TLSNextProto, "when checking .TLSNextProto")
+	assert.Equal(t, old.MaxResponseHeaderBytes, newT.MaxResponseHeaderBytes, "when checking .MaxResponseHeaderBytes")
+}
+
+type aType struct {
+	Matching      string
+	OnlyA         string
+	MatchingInt   int
+	DifferentType string
+}
+
+type bType struct {
+	Matching      string
+	OnlyB         string
+	MatchingInt   int
+	DifferentType int
+	Unused        string
+}
+
+func TestSetFrom(t *testing.T) {
+	a := aType{
+		Matching:      "a",
+		OnlyA:         "onlyA",
+		MatchingInt:   1,
+		DifferentType: "suprise",
+	}
+
+	b := bType{
+		Matching:      "b",
+		OnlyB:         "onlyB",
+		MatchingInt:   2,
+		DifferentType: 7,
+		Unused:        "Ha",
+	}
+	bBefore := b
+
+	SetFrom(&a, &b)
+
+	assert.Equal(t, aType{
+		Matching:      "b",
+		OnlyA:         "onlyA",
+		MatchingInt:   2,
+		DifferentType: "suprise",
+	}, a)
+
+	assert.Equal(t, bBefore, b)
+}
+
+func TestSetFromReversed(t *testing.T) {
+	a := aType{
+		Matching:      "a",
+		OnlyA:         "onlyA",
+		MatchingInt:   1,
+		DifferentType: "suprise",
+	}
+	aBefore := a
+
+	b := bType{
+		Matching:      "b",
+		OnlyB:         "onlyB",
+		MatchingInt:   2,
+		DifferentType: 7,
+		Unused:        "Ha",
+	}
+
+	SetFrom(&b, &a)
+
+	assert.Equal(t, bType{
+		Matching:      "a",
+		OnlyB:         "onlyB",
+		MatchingInt:   1,
+		DifferentType: 7,
+		Unused:        "Ha",
+	}, b)
+
+	assert.Equal(t, aBefore, a)
+}