additional test for expected states

test/spec/Stream.ts

@@ -96,4 +96,122 @@ describe ('stream', () => {
     stream.end_graph ();
     stream.end ();
   }));
+
+  // eslint-disable-next-line max-lines-per-function
+  it ('should reject invalid command sequences', () => {
+    /**
+     * command  valid                 invalid
+     * [s]      cug, cdg              eg, cn, csg, ce, at
+     * cn       eg, cn, csg, ce, at   cug, cdg
+     * cug      eg, cn, csg, ce, at   cug, cdg
+     * cdg      eg, cn, csg, ce, at   cug, cdg
+     * csg      eg, cn, csg, ce, at   cug, cdg
+     * eg       eg, cn, csg, ce       cug, cdg, at
+     * at       eg, cn, csg, ce       cug, cdg, at
+     * ce       eg, cn, csg, ce, at   cug, cdg
+     */
+
+    const cn = (g:GraphStream) => {
+      g.create_node ('foo');
+    };
+    const cug = (g:GraphStream) => {
+      g.create_graph ('foo', 'u');
+    };
+    const cdg = (g:GraphStream) => {
+      g.create_graph ('foo', 'd');
+    };
+    const csg = (g:GraphStream) => {
+      g.create_graph ('foo', 's');
+    };
+    const eg = (g:GraphStream) => {
+      g.end_graph ();
+    };
+    const at = (g:GraphStream) => {
+      g.attributes ({ color: 'red' });
+    };
+    const ce = (g:GraphStream) => {
+      g.create_edge ('foo', 'bar');
+    };
+
+    const combinations = [
+      {
+        primary: (g:GraphStream) => {
+          cug (g);
+          cn (g);
+        },
+        secondary: [
+          cug,
+          cdg
+        ]
+      },
+      {
+        primary:   cug,
+        secondary: [
+          cug,
+          cdg
+        ]
+      },
+      {
+        primary:   cdg,
+        secondary: [
+          cug,
+          cdg
+        ]
+      },
+      {
+        primary:   (g:GraphStream) => {
+          cug (g);
+          csg (g);
+        },
+        secondary: [
+          cug,
+          cdg
+        ]
+      },
+      {
+        primary:   (g:GraphStream) => {
+          cug (g);
+          csg (g);
+          eg (g);
+        },
+        secondary: [
+          cug,
+          cdg,
+          at
+        ]
+      },
+      {
+        primary:   (g:GraphStream) => {
+          cug (g);
+          at (g);
+        },
+        secondary: [
+          cug,
+          cdg,
+          at
+        ]
+      },
+      {
+        primary:   (g:GraphStream) => {
+          cug (g);
+          ce (g);
+        },
+        secondary: [
+          cug,
+          cdg
+        ]
+      }
+    ];
+
+    for (const comb of combinations) {
+      for (const secondary of comb.secondary) {
+        const g = (new GraphStream);
+        comb.primary (g);
+        expect (() => secondary (g))
+          .toThrowError (
+            /invalid state to execute command.*?expected:.*?actual:/uis
+          );
+      }
+    }
+  });
 });