testscript: test custom conditions

testscript/doc.go

@@ -120,6 +120,35 @@ when testing.Short() is false.
 
 Additional conditions can be added by passing a function to Params.Condition.
 
+An example:
+
+		Condition: func(cond string) (bool, error) {
+			// Assume condition name and args are separated by colon (":")
+			args := strings.Split(cond, ":")
+			// Empty condition is already managed in testscript.run()
+			name := args[0]
+			switch name {
+			case "is_upper":
+				if len(args) < 2 {
+					return false, fmt.Errorf("syntax: [is_upper:word]")
+				}
+				return strings.ToUpper(args[1]) == args[1], nil
+			case "always_true":
+				return true, nil
+			default:
+				return false, fmt.Errorf("unrecognized condition %s", name)
+			}
+		},
+
+With the conditions so defined, you can use them as follows:
+
+	env upper_word=ABCD
+	env lower_word=abcd
+	# the first two conditions will allow the 'echo' command to run. The third one will go silent.
+	[always_true] exec echo 'this is true'
+	[is_upper:$upper_word] exec echo 'found an uppercase word'
+	[is_upper:$lower_word] exec echo 'found an uppercase word'
+
 The predefined commands are:
 
   - cd dir

testscript/testdata/custom_conditions.txt

@@ -0,0 +1,67 @@
+[!exec:echo] skip
+
+env upper_word=ABCD
+env lower_word=abcd
+
+[always_true] exec echo 'this is true'
+stdout 'this is true'
+
+exec echo ''
+
+[!always_true] exec echo 'this is true'
+! stdout .
+
+exec echo ''
+
+[always_false] exec echo 'this is false'
+! stdout .
+
+exec echo ''
+
+[!always_false] exec echo 'this is false'
+stdout 'this is false'
+
+exec echo ''
+
+[is_upper:ABCD] exec echo 'it is upper'
+stdout 'it is upper'
+
+exec echo ''
+
+[is_upper:$upper_word] exec echo 'it is again upper'
+stdout 'it is again upper'
+
+exec echo ''
+
+[is_upper:abcd] exec echo 'it is upper'
+! stdout .
+
+exec echo ''
+
+[is_upper:$lower_word] exec echo 'it is lower'
+! stdout .
+
+exec echo ''
+
+[!is_upper:ABCD] exec echo 'it is upper'
+! stdout .
+
+exec echo ''
+
+[is_lower:abcd] exec echo  'it is lower'
+stdout 'it is lower'
+
+exec echo ''
+
+[is_lower:$lower_word] exec echo  'it is again lower'
+stdout 'it is again lower'
+
+exec echo ''
+
+[is_lower:ABCD] exec echo 'it is lower'
+! stdout .
+
+exec echo ''
+
+[!is_lower:$lower_word] exec echo 'it is lower'
+! stdout .

testscript/testscript_test.go

@@ -222,6 +222,30 @@ func TestScripts(t *testing.T) {
 				}
 			},
 		},
+		Condition: func(cond string) (bool, error) {
+			// Assume condition name and args are separated by colon (":")
+			args := strings.Split(cond, ":")
+			// Empty condition is already managed in testscript.run()
+			name := args[0]
+			switch name {
+			case "is_upper":
+				if len(args) < 2 {
+					return false, fmt.Errorf("syntax: [is_upper:word]")
+				}
+				return strings.ToUpper(args[1]) == args[1], nil
+			case "is_lower":
+				if len(args) < 2 {
+					return false, fmt.Errorf("syntax: [is_lower:word]")
+				}
+				return strings.ToLower(args[1]) == args[1], nil
+			case "always_true":
+				return true, nil
+			case "always_false":
+				return false, nil
+			default:
+				return false, fmt.Errorf("unrecognized condition %s", name)
+			}
+		},
 		Setup: func(env *Env) error {
 			infos, err := ioutil.ReadDir(env.WorkDir)
 			if err != nil {