Add specs for tasks

spec/build_tests_spec.rb

@@ -2841,4 +2841,64 @@ EOF
     end
   end
 
+  it "executes the requested tasks in the requested order" do
+    test_dir "tasks"
+    result = run_rscons(args: %w[-f tasks.rb configure])
+    result = run_rscons(args: %w[-f tasks.rb one three])
+    expect(result.stderr).to eq ""
+    expect(result.status).to eq 0
+    expect(result.stdout).to eq "one\nthree\n"
+    result = run_rscons(args: %w[-f tasks.rb three one])
+    expect(result.stderr).to eq ""
+    expect(result.status).to eq 0
+    expect(result.stdout).to eq "three\none\n"
+  end
+
+  it "executes the task's dependencies before the requested task" do
+    test_dir "tasks"
+    result = run_rscons(args: %w[-f tasks.rb configure])
+    result = run_rscons(args: %w[-f tasks.rb two])
+    expect(result.stderr).to eq ""
+    expect(result.status).to eq 0
+    expect(result.stdout).to eq "one\nthree\ntwo\n"
+  end
+
+  it "does not execute a task more than once" do
+    test_dir "tasks"
+    result = run_rscons(args: %w[-f tasks.rb configure])
+    result = run_rscons(args: %w[-f tasks.rb one two three])
+    expect(result.stderr).to eq ""
+    expect(result.status).to eq 0
+    expect(result.stdout).to eq "one\nthree\ntwo\n"
+  end
+
+  it "passes task arguments" do
+    test_dir "tasks"
+    result = run_rscons(args: %w[-f tasks.rb configure])
+    result = run_rscons(args: %w[-f tasks.rb four])
+    expect(result.stderr).to eq ""
+    expect(result.status).to eq 0
+    expect(result.stdout).to eq %[four\nmyparam:"defaultvalue"\nmyp2:nil\n]
+    result = run_rscons(args: %w[-f tasks.rb four --myparam=cli-value --myp2 one])
+    expect(result.stderr).to eq ""
+    expect(result.status).to eq 0
+    expect(result.stdout).to eq %[four\nmyparam:"cli-value"\nmyp2:"--myp2"\none\n]
+  end
+
+  it "displays tasks and their arguments in the help info" do
+    test_dir "tasks"
+    result = run_rscons(args: %w[-f tasks.rb -h])
+    expect(result.stderr).to eq ""
+    expect(result.status).to eq 0
+    verify_lines(lines(result.stdout), [
+      "Tasks:",
+      /\bthree\b\s+Task three/,
+      /\bfour\b\s+Task four/,
+      /--myparam=MYPARAM\s+My special parameter/,
+      /--myp2\s+My parameter 2/,
+    ])
+    expect(result.stdout).to_not match /^\s*one\b/
+    expect(result.stdout).to_not match /^\s*two\b/
+  end
+
 end