feat: improve install error when app doesnt exist

cmd/install.go

@@ -4,14 +4,17 @@
 package cmd
 
 import (
+	"errors"
 	"fmt"
 	"os"
 	"sort"
+	"strings"
 
 	"github.com/olekukonko/tablewriter"
 	"github.com/spf13/cobra"
 
 	"github.com/alexellis/arkade/cmd/apps"
+	"github.com/alexellis/arkade/pkg/get"
 )
 
 type ArkadeApp struct {
@@ -100,7 +103,7 @@ To request a new app, raise a GitHub issue at:
 			}
 		}
 		if app == nil {
-			return fmt.Errorf("no such app: %s, run \"arkade install --help\" for a list of apps", name)
+			return errors.New(checkForTool(name, get.MakeTools()))
 		}
 
 		return nil
@@ -181,3 +184,13 @@ func NewArkadeApp(cmd func() *cobra.Command, msg string) ArkadeApp {
 		InfoMessage: msg,
 	}
 }
+
+func checkForTool(appName string, tools []get.Tool) string {
+
+	for _, tool := range tools {
+		if strings.EqualFold(tool.Name, appName) {
+			return fmt.Sprintf("no such app. %s is available as a tool, run \"arkade get %s\" to get it", appName, appName)
+		}
+	}
+	return fmt.Sprintf("no such app: %s, run \"arkade install --help\" for a list of apps", appName)
+}

cmd/install_test.go

@@ -0,0 +1,91 @@
+// Copyright (c) arkade author(s) 2022. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+package cmd
+
+import (
+	"testing"
+
+	"github.com/alexellis/arkade/pkg/get"
+)
+
+type Tool = get.Tool
+
+func TestCheckForTool(t *testing.T) {
+	tests := []struct {
+		name       string
+		appName    string
+		tools      []Tool
+		expected   string
+		expectFail bool
+	}{
+		{
+			name:    "Tool exists but expected is wrong",
+			appName: "kubectl",
+			tools: []Tool{
+				{Name: "kubectl"},
+				{Name: "helm"},
+				{Name: "k9s"},
+			},
+			expected:   "this test should fail",
+			expectFail: true,
+		},
+		{
+			name:    "Tool exists",
+			appName: "kubectl",
+			tools: []Tool{
+				{Name: "kubectl"},
+				{Name: "helm"},
+				{Name: "k9s"},
+			},
+			expected:   "no such app. kubectl is available as a tool, run \"arkade get kubectl\" to get it",
+			expectFail: false,
+		},
+		{
+			name:    "Tool does not exist",
+			appName: "randomtool",
+			tools: []Tool{
+				{Name: "kubectl"},
+				{Name: "helm"},
+			},
+			expected:   "no such app: randomtool, run \"arkade install --help\" for a list of apps",
+			expectFail: false,
+		},
+		{
+			name:    "Case-insensitive match",
+			appName: "KUBECTL",
+			tools: []Tool{
+				{Name: "kubectl"},
+				{Name: "helm"},
+			},
+			expected:   "no such app. KUBECTL is available as a tool, run \"arkade get KUBECTL\" to get it",
+			expectFail: false,
+		},
+		{
+			name:       "Empty tool list",
+			appName:    "kubectl",
+			tools:      []Tool{},
+			expected:   "no such app: kubectl, run \"arkade install --help\" for a list of apps",
+			expectFail: false,
+		},
+		{
+			name:    "Empty app name",
+			appName: "",
+			tools: []Tool{
+				{Name: "kubectl"},
+			},
+			expected:   "no such app: , run \"arkade install --help\" for a list of apps",
+			expectFail: false,
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			result := checkForTool(tc.appName, tc.tools)
+			if result != tc.expected && !tc.expectFail {
+				t.Errorf("%s\nwant: %s\n got: %s",
+					tc.name, tc.expected, result)
+			}
+		})
+	}
+}