Add a version of table.Entry that allows dumping the entry parameters.

Sometimes, it's useful to have the parameters of a given table entry as part of the description of the It counterpart. To achieve that, we allow passing a function as the description parameter. In case a string is passed, the previous behaviour is preserved. In case of function, it is expected to return a string that will be used as the new description for the generated It.
onsi · Jun 8, 2020 · bce59f1 · bce59f1
1 parent a912ec5
commit bce59f1
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Showing 2 changed files with 122 additions and 23 deletions.
diff --git a/extensions/table/table_entry.go b/extensions/table/table_entry.go
@@ -1,6 +1,7 @@
 package table
 
 import (
+	"fmt"
 	"reflect"
 
 	"github.com/onsi/ginkgo/internal/codelocation"
@@ -12,7 +13,7 @@ import (
 TableEntry represents an entry in a table test.  You generally use the `Entry` constructor.
 */
 type TableEntry struct {
-	Description  string
+	Description  interface{}
 	Parameters   []interface{}
 	Pending      bool
 	Focused      bool
@@ -26,33 +27,56 @@ func (t TableEntry) generateIt(itBody reflect.Value) {
 		t.codeLocation = codelocation.New(5)
 	}
 
-	if t.Pending {
-		global.Suite.PushItNode(t.Description, func() {}, types.FlagTypePending, t.codeLocation, 0)
-		return
+	var description string
+	descriptionValue := reflect.ValueOf(t.Description)
+	switch descriptionValue.Kind() {
+	case reflect.String:
+		description = descriptionValue.String()
+	case reflect.Func:
+		values := castParameters(descriptionValue, t.Parameters)
+		res := descriptionValue.Call(values)
+		if len(res) != 1 {
+			panic(fmt.Sprintf("The describe function should return only a value, returned %d", len(res)))
+		}
+		if res[0].Kind() != reflect.String {
+			panic(fmt.Sprintf("The describe function should return a string, returned %#v", res[0]))
+		}
+		description = res[0].String()
+	default:
+		panic(fmt.Sprintf("Description can either be a string or a function, got %#v", descriptionValue))
 	}
 
-	values := make([]reflect.Value, len(t.Parameters))
-	iBodyType := itBody.Type()
-	for i, param := range t.Parameters {
-		if param == nil {
-			inType := iBodyType.In(i)
-			values[i] = reflect.Zero(inType)
-		} else {
-			values[i] = reflect.ValueOf(param)
-		}
+	if t.Pending {
+		global.Suite.PushItNode(description, func() {}, types.FlagTypePending, t.codeLocation, 0)
+		return
 	}
 
+	values := castParameters(itBody, t.Parameters)
 	body := func() {
 		itBody.Call(values)
 	}
 
 	if t.Focused {
-		global.Suite.PushItNode(t.Description, body, types.FlagTypeFocused, t.codeLocation, global.DefaultTimeout)
+		global.Suite.PushItNode(description, body, types.FlagTypeFocused, t.codeLocation, global.DefaultTimeout)
 	} else {
-		global.Suite.PushItNode(t.Description, body, types.FlagTypeNone, t.codeLocation, global.DefaultTimeout)
+		global.Suite.PushItNode(description, body, types.FlagTypeNone, t.codeLocation, global.DefaultTimeout)
 	}
 }
 
+func castParameters(function reflect.Value, parameters []interface{}) []reflect.Value {
+	res := make([]reflect.Value, len(parameters))
+	funcType := function.Type()
+	for i, param := range parameters {
+		if param == nil {
+			inType := funcType.In(i)
+			res[i] = reflect.Zero(inType)
+		} else {
+			res[i] = reflect.ValueOf(param)
+		}
+	}
+	return res
+}
+
 /*
 Entry constructs a TableEntry.
 
@@ -61,27 +85,51 @@ Subsequent parameters are saved off and sent to the callback passed in to `Descr
 
 Each Entry ends up generating an individual Ginkgo It.
 */
-func Entry(description string, parameters ...interface{}) TableEntry {
-	return TableEntry{description, parameters, false, false, codelocation.New(1)}
+func Entry(description interface{}, parameters ...interface{}) TableEntry {
+	return TableEntry{
+		Description:  description,
+		Parameters:   parameters,
+		Pending:      false,
+		Focused:      false,
+		codeLocation: codelocation.New(1),
+	}
 }
 
 /*
 You can focus a particular entry with FEntry.  This is equivalent to FIt.
 */
-func FEntry(description string, parameters ...interface{}) TableEntry {
-	return TableEntry{description, parameters, false, true, codelocation.New(1)}
+func FEntry(description interface{}, parameters ...interface{}) TableEntry {
+	return TableEntry{
+		Description:  description,
+		Parameters:   parameters,
+		Pending:      false,
+		Focused:      true,
+		codeLocation: codelocation.New(1),
+	}
 }
 
 /*
 You can mark a particular entry as pending with PEntry.  This is equivalent to PIt.
 */
-func PEntry(description string, parameters ...interface{}) TableEntry {
-	return TableEntry{description, parameters, true, false, codelocation.New(1)}
+func PEntry(description interface{}, parameters ...interface{}) TableEntry {
+	return TableEntry{
+		Description:  description,
+		Parameters:   parameters,
+		Pending:      true,
+		Focused:      false,
+		codeLocation: codelocation.New(1),
+	}
 }
 
 /*
 You can mark a particular entry as pending with XEntry.  This is equivalent to XIt.
 */
-func XEntry(description string, parameters ...interface{}) TableEntry {
-	return TableEntry{description, parameters, true, false, codelocation.New(1)}
+func XEntry(description interface{}, parameters ...interface{}) TableEntry {
+	return TableEntry{
+		Description:  description,
+		Parameters:   parameters,
+		Pending:      true,
+		Focused:      false,
+		codeLocation: codelocation.New(1),
+	}
 }
diff --git a/extensions/table/table_test.go b/extensions/table/table_test.go
@@ -1,6 +1,7 @@
 package table_test
 
 import (
+	"fmt"
 	"strings"
 
 	. "github.com/onsi/ginkgo/extensions/table"
@@ -62,3 +63,53 @@ var _ = Describe("Table", func() {
 		Entry("nil", nil),
 	)
 })
+
+var _ = Describe("TableWithParametricDescription", func() {
+	describe := func(desc string) func(int, int, bool) string {
+		return func(x, y int, expected bool) string {
+			return fmt.Sprintf("%s x=%d y=%d expected:%t", desc, x, y, expected)
+		}
+	}
+
+	DescribeTable("a simple table",
+		func(x int, y int, expected bool) {
+			Ω(x > y).Should(Equal(expected))
+		},
+		Entry(describe("x > y"), 1, 0, true),
+		Entry(describe("x == y"), 0, 0, false),
+		Entry(describe("x < y"), 0, 1, false),
+	)
+
+	type ComplicatedThings struct {
+		Superstructure string
+		Substructure   string
+		Count          int
+	}
+
+	describeComplicated := func(desc string) func(ComplicatedThings) string {
+		return func(things ComplicatedThings) string {
+			return fmt.Sprintf("%s things=%v", desc, things)
+		}
+	}
+
+	DescribeTable("a more complicated table",
+		func(c ComplicatedThings) {
+			Ω(strings.Count(c.Superstructure, c.Substructure)).Should(BeNumerically("==", c.Count))
+		},
+		Entry(describeComplicated("with no matching substructures"), ComplicatedThings{
+			Superstructure: "the sixth sheikh's sixth sheep's sick",
+			Substructure:   "emir",
+			Count:          0,
+		}),
+		Entry(describeComplicated("with one matching substructure"), ComplicatedThings{
+			Superstructure: "the sixth sheikh's sixth sheep's sick",
+			Substructure:   "sheep",
+			Count:          1,
+		}),
+		Entry(describeComplicated("with many matching substructures"), ComplicatedThings{
+			Superstructure: "the sixth sheikh's sixth sheep's sick",
+			Substructure:   "si",
+			Count:          3,
+		}),
+	)
+})