== operator for green trees (#275)

Also add some more direct GreeNode tests

Author: c42f

src/green_tree.jl

@@ -55,6 +55,10 @@ head(node::GreenNode)        = node.head
 
 Base.summary(node::GreenNode) = summary(node.head)
 
+function Base.:(==)(n1::GreenNode, n2::GreenNode)
+    n1.head == n2.head && n1.span == n2.span && n1.args == n2.args
+end
+
 # Pretty printing
 function _show_green_node(io, node, indent, pos, str, show_trivia)
     if !show_trivia && is_trivia(node)

test/green_node.jl

@@ -0,0 +1,54 @@
+@testset "GreenNode" begin
+    t = parsestmt(GreenNode, "aa + b")
+
+    @test span(t) == 6
+    @test haschildren(t)
+    @test head(t) == SyntaxHead(K"call", 0x0008)
+    @test span.(children(t)) == [2,1,1,1,1]
+    @test head.(children(t)) == [
+         SyntaxHead(K"Identifier", 0x0000)
+         SyntaxHead(K"Whitespace", 0x0001)
+         SyntaxHead(K"+", 0x0000)
+         SyntaxHead(K"Whitespace", 0x0001)
+         SyntaxHead(K"Identifier", 0x0000)
+    ]
+
+    t2 = parsestmt(GreenNode, "aa + b")
+    @test t == t2
+    @test t !== t2
+
+    text = "f(@x(y), z)"
+    @test sprint(show, MIME("text/plain"), parsestmt(GreenNode, text)) ==
+    """
+         1:11     │[call]
+         1:1      │  Identifier             ✔
+         2:2      │  (
+         3:7      │  [macrocall]
+         3:3      │    @
+         4:4      │    MacroName            ✔
+         5:5      │    (
+         6:6      │    Identifier           ✔
+         7:7      │    )
+         8:8      │  ,
+         9:9      │  Whitespace
+        10:10     │  Identifier             ✔
+        11:11     │  )
+    """
+
+    @test sprint(show, MIME("text/plain"), parsestmt(GreenNode, text), text) ==
+    """
+         1:11     │[call]
+         1:1      │  Identifier             ✔   "f"
+         2:2      │  (                          "("
+         3:7      │  [macrocall]
+         3:3      │    @                        "@"
+         4:4      │    MacroName            ✔   "x"
+         5:5      │    (                        "("
+         6:6      │    Identifier           ✔   "y"
+         7:7      │    )                        ")"
+         8:8      │  ,                          ","
+         9:9      │  Whitespace                 " "
+        10:10     │  Identifier             ✔   "z"
+        11:11     │  )                          ")"
+    """
+end

test/runtests.jl

@@ -51,6 +51,7 @@ end
 
 include("parse_stream.jl")
 include("parser.jl")
+include("green_node.jl")
 include("syntax_tree.jl")
 include("diagnostics.jl")
 include("parser_api.jl")

test/test_utils.jl

@@ -20,6 +20,9 @@ using .JuliaSyntax:
     # Node inspection
     kind,
     flags,
+    head,
+    span,
+    SyntaxHead,
     is_trivia,
     sourcetext,
     haschildren,