Improve loop function (#78)

README.md

@@ -300,8 +300,10 @@ functions:
 - `Odd`
 - `Even`
 
-If you need to create your own loop for advanced templates you can use the `{{ Loop }}` function. This function takes a single integer as parameter which is
-the number of iterations. `Loop` must be used with `range` e.g.
+If you need to create your own loop for advanced templates you can use the `{{ Loop }}` function.
+
+This function takes a single integer as parameter which is the number of
+iterations. `Loop` must be used with `range` e.g.
 
 ```html
 {{ range Loop 10 }} You're going to see this 10 times! {{ end }}
@@ -316,11 +318,12 @@ example:
 ```
 
 In combination with `Loop` and `range` you can use `Odd` and `Even` to determine
-if the current iteration is odd or even. This is especially helpful when
-creating HTML tables:
+if the current iteration is odd or even.
+
+For example, this is helpful when creating HTML tables:
 
 ```html
-{{ range $i, $j := Loop 5 }}
+{{ range $i := Loop 5 }}
 <tr>
   {{ if Odd $i -}}
   <td class="odd">{{- else -}}</td>
@@ -334,8 +337,10 @@ creating HTML tables:
 values of `Loop 5` to the variables `$i` and `$j`.
 
 Templates also support string manipulation via the `printf` function. Using
-`printf` we can create custom output. For example to display a full name in the
-format `Lastname Firstname` instead of `Firstname Lastname`.
+`printf` we can create custom output.
+
+For example, to display a full name in the format `Lastname Firstname` instead
+of `Firstname Lastname`.
 
 ```html
 {{ printf "%s %s" Name.Last Name.First }}

integration/cli_test.go

@@ -1,11 +1,7 @@
-package main
+package integration
 
 import (
-	"flag"
-	"fmt"
-	"os"
 	"os/exec"
-	"path/filepath"
 	"regexp"
 	"testing"
 
@@ -14,16 +10,6 @@ import (
 	"github.com/lucapette/fakedata/testutil"
 )
 
-// In these tests, there's a lot going on. Have a look at this article for a
-// longer explanation:
-// https://lucapette.me/writing/writing-integration-tests-for-a-go-cli-application
-
-var update = flag.Bool("update", false, "update golden files")
-
-const binaryName = "fakedata"
-
-var binaryPath string
-
 func TestCLI(t *testing.T) {
 	tests := []struct {
 		name    string
@@ -199,86 +185,3 @@ func TestFileGenerator(t *testing.T) {
 		})
 	}
 }
-
-var templateTests = []struct {
-	tmpl    string
-	golden  string
-	wantErr bool
-}{
-	{"simple.tmpl", "simple-template.golden", false},
-	{"loop.tmpl", "loop.golden", false},
-	{"broken.tmpl", "broken-template.golden", true},
-	{"unknown-function.tmpl", "unknown-function.golden", true},
-}
-
-func TestTemplatesWithCLIArgs(t *testing.T) {
-	for _, tt := range templateTests {
-		t.Run(tt.tmpl, func(t *testing.T) {
-			cmd := exec.Command(binaryPath, "--template", fmt.Sprintf("testutil/fixtures/%s", tt.tmpl))
-			output, err := cmd.CombinedOutput()
-			if (err != nil) != tt.wantErr {
-				t.Fatalf("%s\nexpected (err != nil) to be %v, but got %v. err: %v", output, tt.wantErr, err != nil, err)
-			}
-
-			golden := testutil.NewGoldenFile(t, tt.golden)
-			actual := string(output)
-			if *update {
-				golden.Write(actual)
-			}
-
-			expected := golden.Load()
-
-			if !reflect.DeepEqual(actual, expected) {
-				t.Fatalf("diff: %v", testutil.Diff(expected, actual))
-			}
-		})
-	}
-}
-
-func TestTemplatesWithPipe(t *testing.T) {
-	for _, tt := range templateTests {
-		t.Run(tt.tmpl, func(t *testing.T) {
-			fixture := testutil.NewFixture(t, tt.tmpl)
-			cmd := exec.Command(binaryPath)
-			cmd.Stdin = fixture.AsFile()
-			output, err := cmd.CombinedOutput()
-			if (err != nil) != tt.wantErr {
-				t.Fatalf("%s\nexpected (err != nil) to be %v, but got %v. err: %v", output, tt.wantErr, err != nil, err)
-			}
-
-			golden := testutil.NewGoldenFile(t, tt.golden)
-			actual := string(output)
-			if *update {
-				golden.Write(actual)
-			}
-
-			expected := golden.Load()
-
-			if !reflect.DeepEqual(actual, expected) {
-				t.Fatalf("diff: %v", testutil.Diff(expected, actual))
-			}
-		})
-	}
-}
-
-func TestMain(m *testing.M) {
-	err := os.Chdir("..")
-	if err != nil {
-		fmt.Printf("could not change dir: %v", err)
-		os.Exit(1)
-	}
-
-	abs, err := filepath.Abs(binaryName)
-	if err != nil {
-		fmt.Printf("could not get abs path for %s: %v", binaryName, err)
-		os.Exit(1)
-	}
-
-	binaryPath = abs
-
-	if err := exec.Command("make").Run(); err != nil {
-		fmt.Printf("could not make binary for %s: %v", binaryName, err)
-		os.Exit(1)
-	}
-	os.Exit(m.Run())
-}

integration/setup_test.go

@@ -0,0 +1,42 @@
+package integration
+
+import (
+	"flag"
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"testing"
+)
+
+// In these tests, there's a lot going on. Have a look at this article for a
+// longer explanation:
+// https://lucapette.me/writing/writing-integration-tests-for-a-go-cli-application
+
+var update = flag.Bool("update", false, "update golden files")
+
+const binaryName = "fakedata"
+
+var binaryPath string
+
+func TestMain(m *testing.M) {
+	err := os.Chdir("..")
+	if err != nil {
+		fmt.Printf("could not change dir: %v", err)
+		os.Exit(1)
+	}
+
+	abs, err := filepath.Abs(binaryName)
+	if err != nil {
+		fmt.Printf("could not get abs path for %s: %v", binaryName, err)
+		os.Exit(1)
+	}
+
+	binaryPath = abs
+
+	if err := exec.Command("make").Run(); err != nil {
+		fmt.Printf("could not make binary for %s: %v", binaryName, err)
+		os.Exit(1)
+	}
+	os.Exit(m.Run())
+}

integration/templates_test.go

@@ -0,0 +1,72 @@
+package integration
+
+import (
+	"fmt"
+	"os/exec"
+	"reflect"
+	"testing"
+
+	"github.com/lucapette/fakedata/testutil"
+)
+
+var templateTests = []struct {
+	tmpl    string
+	golden  string
+	wantErr bool
+}{
+	{"simple.tmpl", "simple-template.golden", false},
+	{"loop.tmpl", "loop.golden", false},
+	{"loop-with-index.tmpl", "loop-with-index.golden", false},
+	{"broken.tmpl", "broken-template.golden", true},
+	{"unknown-function.tmpl", "unknown-function.golden", true},
+}
+
+func TestTemplatesWithCLIArgs(t *testing.T) {
+	for _, tt := range templateTests {
+		t.Run(tt.tmpl, func(t *testing.T) {
+			cmd := exec.Command(binaryPath, "--template", fmt.Sprintf("testutil/fixtures/%s", tt.tmpl))
+			output, err := cmd.CombinedOutput()
+			if (err != nil) != tt.wantErr {
+				t.Fatalf("%s\nexpected (err != nil) to be %v, but got %v. err: %v", output, tt.wantErr, err != nil, err)
+			}
+
+			golden := testutil.NewGoldenFile(t, tt.golden)
+			actual := string(output)
+			if *update {
+				golden.Write(actual)
+			}
+
+			expected := golden.Load()
+
+			if !reflect.DeepEqual(actual, expected) {
+				t.Fatalf("diff: %v", testutil.Diff(expected, actual))
+			}
+		})
+	}
+}
+
+func TestTemplatesWithPipe(t *testing.T) {
+	for _, tt := range templateTests {
+		t.Run(tt.tmpl, func(t *testing.T) {
+			fixture := testutil.NewFixture(t, tt.tmpl)
+			cmd := exec.Command(binaryPath)
+			cmd.Stdin = fixture.AsFile()
+			output, err := cmd.CombinedOutput()
+			if (err != nil) != tt.wantErr {
+				t.Fatalf("%s\nexpected (err != nil) to be %v, but got %v. err: %v", output, tt.wantErr, err != nil, err)
+			}
+
+			golden := testutil.NewGoldenFile(t, tt.golden)
+			actual := string(output)
+			if *update {
+				golden.Write(actual)
+			}
+
+			expected := golden.Load()
+
+			if !reflect.DeepEqual(actual, expected) {
+				t.Fatalf("diff: %v", testutil.Diff(expected, actual))
+			}
+		})
+	}
+}

pkg/fakedata/template.go

@@ -37,7 +37,12 @@ func (tf templateFactory) getFunctions() template.FuncMap {
 				}
 			}
 
-			return make([]int, n)
+			times := make([]int, n)
+			for i := 0; i < n; i++ {
+				times[i] = i
+			}
+
+			return times
 		},
 		"Odd":  func(i int) bool { return i%2 != 0 },
 		"Even": func(i int) bool { return i%2 == 0 },

testutil/fixtures/loop-with-index.tmpl

@@ -0,0 +1 @@
+{{range $i := Loop 5}}{{$i}}{{end}}

testutil/golden/loop-with-index.golden

@@ -0,0 +1,10 @@
+01234
+01234
+01234
+01234
+01234
+01234
+01234
+01234
+01234
+01234