Fix alias usage in help command

- Add info about aliases into model structure used by help
  command templating.
- Add some tests to models.
- Change help commands list to group command and its aliases together.
- Change help command to show aliases.
- Fixes #458
- Fixes #426

spring-shell-standard-commands/src/main/java/org/springframework/shell/standard/commands/CommandInfoModel.java

@@ -33,13 +33,15 @@ import org.springframework.util.StringUtils;
 class CommandInfoModel {
 
 	private String name;
+	private List<String> aliases;
 	private String description;
 	private List<CommandParameterInfoModel> parameters;
 	private CommandAvailabilityInfoModel availability;
 
-	CommandInfoModel(String name, String description, List<CommandParameterInfoModel> parameters,
+	CommandInfoModel(String name, List<String> aliases, String description, List<CommandParameterInfoModel> parameters,
 			CommandAvailabilityInfoModel availability) {
 		this.name = name;
+		this.aliases = aliases;
 		this.description = description;
 		this.parameters = parameters;
 		this.availability = availability;
@@ -68,6 +70,9 @@ class CommandInfoModel {
 			})
 			.collect(Collectors.toList());
 
+		List<String> aliases = registration.getAliases().stream().map(ca -> ca.getCommand())
+				.collect(Collectors.toList());
+
 		String description = registration.getDescription();
 		boolean available = true;
 		String availReason = "";
@@ -77,7 +82,7 @@ class CommandInfoModel {
 			availReason = a.getReason();
 		}
 		CommandAvailabilityInfoModel availModel = CommandAvailabilityInfoModel.of(available, availReason);
-		return new CommandInfoModel(name, description, parameters, availModel);
+		return new CommandInfoModel(name, aliases, description, parameters, availModel);
 	}
 
 	private static String commandOptionType(CommandOption o) {
@@ -93,6 +98,10 @@ class CommandInfoModel {
 		return name;
 	}
 
+	public List<String> getAliases() {
+		return this.aliases;
+	}
+
 	public String getDescription() {
 		return description;
 	}

spring-shell-standard-commands/src/main/java/org/springframework/shell/standard/commands/GroupsInfoModel.java

@@ -15,6 +15,7 @@
  */
 package org.springframework.shell.standard.commands;
 
+import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
@@ -54,14 +55,18 @@ class GroupsInfoModel {
 	 * @return a groups info model
 	 */
 	static GroupsInfoModel of(boolean showGroups, Map<String, CommandRegistration> registrations) {
+		// throw away registrations aliases as those are then handled in a model
 		// collect commands into groups with sorting
-		SortedMap<String, Map<String, CommandRegistration>> commandsByGroupAndName = registrations.entrySet().stream()
+		HashSet<CommandRegistration> regsWithoutAliases = new HashSet<>(registrations.values());
+		SortedMap<String, Map<String, CommandRegistration>> commandsByGroupAndName = regsWithoutAliases.stream()
+			.collect(Collectors.toMap(r -> r.getCommand(), r -> r)).entrySet().stream()
 			.collect(Collectors.groupingBy(
 				e -> StringUtils.hasText(e.getValue().getGroup()) ? e.getValue().getGroup() : "Default",
 				TreeMap::new,
 				Collectors.toMap(Entry::getKey, Entry::getValue)
 			));
 
+
 		// build model
 		List<GroupCommandInfoModel> gcims = commandsByGroupAndName.entrySet().stream()
 			.map(e -> {

spring-shell-standard-commands/src/main/resources/template/help-command-default.stg

@@ -66,6 +66,14 @@ availability(availability) ::= <<
 <endif>
 >>
 
+// ALIASES
+aliases(aliases) ::= <<
+<if(aliases)>
+<("ALSO KNOWN AS"); format="style-highlight">
+       <(aliases); separator=", ">
+<endif>
+>>
+
 // main
 main(model) ::= <<
 <name(model.name, model.description)>
@@ -74,4 +82,5 @@ main(model) ::= <<
 
 <options(model.parameters)>
 <availability(model.availability)>
+<aliases(model.aliases)>
 >>

spring-shell-standard-commands/src/main/resources/template/help-commands-default.stg

@@ -16,8 +16,12 @@ availabilityDesc(hasUnavailableCommands) ::= <<
 <endif>
 >>
 
+commandName(command) ::= <%
+<[command.name, command.aliases]; format="style-highlight", separator=", ">
+%>
+
 command(command) ::= <<
-<availability(command.availability)><(command.name); format="style-highlight"><(":"); format="style-highlight"> <command.description>
+<availability(command.availability)><commandName(command); format="style-highlight"><(":"); format="style-highlight"> <command.description>
 
 >>