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

#689) 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 9, 2020 · 21eaef2 · 21eaef2
1 parent a912ec5
commit 21eaef2
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Showing 3 changed files with 141 additions and 23 deletions.
diff --git a/extensions/table/table.go b/extensions/table/table.go
@@ -42,6 +42,25 @@ Under the hood, `DescribeTable` simply generates a new Ginkgo `Describe`.  Each
 It's important to understand that the `Describe`s and `It`s are generated at evaluation time (i.e. when Ginkgo constructs the tree of tests and before the tests run).
 
 Individual Entries can be focused (with FEntry) or marked pending (with PEntry or XEntry).  In addition, the entire table can be focused or marked pending with FDescribeTable and PDescribeTable/XDescribeTable.
+
+A description function can be passed to Entry in place of the description. The function is then fed with the entry parameters to generate the description of the It corresponding to that particular Entry.
+
+For example:
+
+	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),
+	)
 */
 func DescribeTable(description string, itBody interface{}, entries ...TableEntry) bool {
 	describeTable(description, itBody, entries, types.FlagTypeNone)

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,
+		}),
+	)
+})